Constructive emergence: why is emergence still considered a mystery?

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Nov 17, 2013 (3 years and 4 months ago)

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11/17/2013

Constructive emergence
: why is emergence still
considered
a mystery?

Russ Abbott

Department of Computer Science, California State University, Los Angeles, California

Russ.Abbott@GMail.com

Abstract
.

Most of what

we call e
mergence is the result of constructive process
es
.
New entities
with

properties considered emergent
are constructed from

i.e.,
i
m-
plemented by

existing
entities. A typical example is

a

steel
-
hulled boat.

Accor
d-
ing to a macro
-
level theory of buo
y
anc
y i
t floats
because of its shape
.
Even though
the boat supervenes over its
steel component
elements, its buoyancy is

neither

r
e-
ducible to
nor predictable from the

properties of steel
. (M
ultiple realizabi
l
ity, i.e.,
that

a boat
c
an

be made
from

many
differe
nt materi
als, is
n

t relevant

at all
.
)

Why

do
es the boat’s heavier
-
than
-
water

components
not sink
?
A
s long as they
are

part
of the

boat’s

implementation, their fate
is downwardly e
n
tailed (not downwardly
caused)

at least in part
by

the
boat
.

Functionalists
have been saying
this sort of
thing

for three decades. Yet emergence is still considered a mystery.
T
his paper
is
intended to

dispel that my
s
tery
.

1.

Introduction

As an outsider

I’m a computer scientist, not a
philosopher

I don’t understand
why emergence is s
till considered a mystery.

For more than three decades, fun
c
tionalist philosophers

s
uch as Putnam
(1975) and Fodor (1974)

have argued for the autonomy of
both
the special sc
i-
ences and

the
regularities

they
explain
.
Here’s Fodor

(1998)

in a widely quoted
p
assage.

The very
existence

of the special sciences testifies to reliable macro
-
level

r
egularities



Damn near everything we know about the world suggests that unimaginably complicated
to
-
ings and fro
-
ings of bits and pieces at the extreme
micro
-
level manag
e somehow to
converge on stable
macro
-
level properties. …

So
regularities exist.
But c
laiming to speak for Kim
(1992)

and
a
pparently a
l-
so for himself

Fodor continues

(somewhat paraphrased)

as fo
l
lows.


2


11/17/2013

The


somehow


really is entirely mysterious
.
Why shoul
d there be (how
could
there be)
macro
-
level regularities
at all

in a world where, by common consent, macro
-
level
stabilities have to supervene on a buzzing, blooming confusion of micro
-
level
interactions.


I’m puzzled by
Fodor’s bafflement
.
The puzzle isn’
t that there are

higher level
entities and properties but why and how they came to be.
A fundamental principle
of functionalism is that

higher level
regularities
are

realized

by lower level ph
e-
nomena

perhaps even
by
buzzing blooming micro
-
level phenomena

a
nd
s
ome
even

in multiple

ways. So why is it mysterious that some
higher
level phenomena
have

actually

been

rea
l
ized
?

But Fodor goes on to
insist
that he doesn’t know why
higher level regularities e
x
ist.

So, then,
why is there anything except physics
? …
Wel
l, I admit that I don’t know why. I
don’t even know how to
think about

why. I expect to figure out why there is anything
except physics the day before I figure out why there is anything at all
.

Is
Fodor

asking

something like

why

are

there human beings rath
er than just

bacteria
,

or
chemicals
,

or elementary physical particles
?

Other than creatio
n
ists or
intelligent design believers,

no one considers this

a mystery
. W
e unde
r
stand
much
of
how it happened.
Put a bunch of elementary particles together, and one ge
t
s

a
t-
oms and then molecules
. The step from there to biological organisms is still
cloudy, but we are close to understanding
it
; w
e will probably be able to cr
e
ate a
biological cell from “inert” chemicals within the next quarter

century
.
Evolution
explains
the rest. So why does Fodor call it
molto my
s
terioso
?

Or

perhaps he

is asking
how

higher level entities emerge from lower level ent
i-
ties
, i.e., what
(
natural
)

processes lead to their emergence
? We understand that
too
.

There are two cases.

(I discuss
this

in more detail in the Section on
E
ntities.)

1.

S
tatic entities, those that are in physical equilibrium (examples include
atoms,
molecules
,

and solar systems), are created
through natural pr
o-
c
esses
because they are in lower energy states than their components

se
p-
a
rately. A hydrogen atom

consisting of a proton and an ele
c
tron

is in a
lower energy state than a proton and an electron not bound together. Na
t-
ural processes te
nd toward minimal energy states

hence the creation
(i.e., emergence) of static entities.

2.

D
ynamic entities, those that require the continual importation of energy to
persist (examples include biological organisms and social systems), are
(likely to be)
created
through natural processes
when their creation results
in
better
access to energy
.
Bett
er

in this case
may mean

any number of
things including

more efficient

access to energy
,
or
access to energy

that
is not accessible to other ent
i
ties
,
or
an ability to keep other entities away
from a source of energy, or some other advantage
. The

emergence

of
the
s
e entities
is

typically the result of evolutionary pro
c
esses.

So we know why and how higher level entities
emerge

from lower level ent
i-
ties.
W
here is the mystery?

3


11/17/2013

How things look from the perspective of a computer scientist

Does the preceding sound

naïve? Am I minimizing the intellectual difficulties?
Computer
s
cien
ce

stud
ies

the conceptualization and implementation of abstra
c-
tions. We build higher level regularities

we call them abstractions

from lower
level regularities.
(See “Abstraction Abstract
ed” (2008).)
That’s what we do for a
li
v
ing

day after day.

Every
software

application is the implementation of higher level abstractions
.
Software applications implement

(i.e., realize)

abstractions by

organizing

lower
level
abstractions

t
ypically those
e
xpressible

in a programming language
.
A
l
t-
hough some people think of software development as a black ar
t
, to many of us
it
’s

the most
natural

thing in the world
.
As software developers w
e know how to
make h
igher level regularities “emerge” from lower level
regularities. All you
need is a programmer

or nature as a blind progra
m
mer.

Software applications and the higher level abstractions they represent supe
r-
vene over

a
very large collection the
lower level abstractions. The “File” menu in
the representation o
f the Microsoft Word document that I’m currently

using, for
example,

supervenes over
data
structures in C++

or wh
ich
ever programming
language Microsoft uses to implement its
applications. The document
I’m
cu
r
ren
t-
ly
writing

supervenes over words, bytes, and

bits in the computer’s disk, d
y
namic
storage, and CPU registers. When Microsoft Word executes

as it is doing as I
write this

the transformation operations that my keystrokes and mouse mov
e-
ments cause to be performed on my document supervene over statement
s in
the
programming language

used in the implementation
, which supervene over i
n
stru
c-
tions at the computer hardware level, which supervene over logic operations pe
r-
formed by gates
, which supervene over still lower level phenomena down to the
quantum level
.
.
Looked at
bottom
-
up
, each level of abstraction

is built

on

has
been made to emerge

from

lower levels

of abstraction

by engineers and pr
o-
grammers. (For an extended discussion of the relationship between levels of a
b-
straction and reductionism, see Abbott,

2008b.) All of this is standard procedure
for computer scie
n
tists.

F
unctionalist philosophers understand
this

computer science
-
based

approach to
abstraction
.

Putnam (1960)

may have been one of the first
philosophers
to intr
o-
duce computational thinking to

philosophy. It has since served

as

one of the pr
i-
mary

foundations of f
unctionalism.

Yet as recently as April 2008 Bedeau an
d

Humphreys (2008) published a volume of

collected articles about emergence.
Their i
n
troduction includes the following.

Emergence r
elates to phenomena that arise from and depend on some more basic
phenomena yet are simultaneously autonomous from that base. The topic of eme
r
gence is
fascinating and controversial in part because emergence seems to be widespread and yet
the very idea of
emergence seems opaque, and perhaps even incoherent.

Are
Bedeau an
d

Humphreys
really saying that the fundamental idea of fun
c-
tionalism

and the standard practice of software
developers

th
at higher level a
b-
4


11/17/2013

stractions
/regularities

may be implemented by lower

level elements and pro
c
es
s-
es

is


opaque and perhaps even incoherent?


Does anyone really
doubt that
higher level abstractions can be implemented by lower level elements and pr
o-
c
esses
?


Perhaps one reason
that this sense of mystery persists
is that Fodor (
1997, en
d-
note 5) argues that Dennett was right to have dismissed th
e

sort of emergence

that
software developers produce.

(I wasn’t able to see where Dennett came to this
conclusion. But Fodor certain does.)

When macrokinds are metaphysically identical to
microkinds
, laws about the latter imply
laws about the former; likewise when macroregularities are logical or mathematical
constructions as in microregularities, as in the “Game of Life,” described by Dennett
(1991). Pace Dennett, such cases do not illumin
ate (what functionalists take to be) the
metaphysical situation in the special sciences. To repeat: autonomy implies ‘real’ (viz
projectible) patterns
without reduction
.

One of the primary examples I use involves macro
-
regularities built within the
Game of

Life. I don’t agree with Fodor
’s claim

that laws about the Game of Life
imply laws about constructs built within the Game of Life.

Later in this paper I
explain what I think is the significance of the fact that one can implement a Turing
machine by organi
zing
Game of Life
patterns.

The real question: reductionism

I know. There’s more to
this issue

than the building of abstractions. In

my som
e-
what
feigned
puzzlement over
Fodor, Bedeau, and Humphreys’

claimed unce
r
tai
n-
ty about the reality of emergence
,

I del
iberately avoid
ed

what is probably the ce
n-
tral
issue:

reductionism. I
f there are
higher level
emergent entities
, and if
one

can
talk about

“laws” to which
these higher level entities
conform
,
doesn’t that pr
o-
duce

a

redundancy between that level of descript
ion and the level of descri
p
tion
that occurs when we use the language of fundamental physics to describe the lo
w-
est level phenomena
over which
the higher level entities supervene
?
If, for e
x
a
m-
ple, I say that a word
disappeared

from my
Microsoft Word
docume
nt because
(a)

I
selected

it
(by double clicking on it)
and then
(b)

I
pressed the delete key,
how does that description relate to the description
given

at the level of bits and
electrons?
Schouten and
Looren

de Jong
(2007) summarize the problem as fo
l-
low
s.

If a higher level explanation can be related to physical processes, it becomes redundant
since the explanatory work can be done by physics.

So i
s my higher level description just a manner of speaking

a
short cut or
convenience for the real action that
is taking place at a far lower level?
If that’s
Fodor’s question
,

it
comes to this. Unless one thinks of nature as causally redu
n-
dant, how can there be both high
er

and low
er

level explanations of high
-
level ph
e-
no
m
ena?


5


11/17/2013

Kim (1998)
, the primary emergent spoi
l sport
,

focuse
d

the question when he
argue
d

that the issue is
not whether some higher level property

is

implementable
(or realizable)

by lower level mechanisms

but whether it is

what
he calls theoret
i-
cal
ly

predictab
le

and reductively explai
n
able
.

What is
being denied by emergentists

is

the theoretical predictability

of

[emergent
property]
E on the basis of

[the
microstructural properties of a system] M: we may know
all that can be known abou
t
M


in particular, laws that govern the entities, properties and

relations constitutive of M


but this knowledge does not suffice to yield a prediction of
E. This unpredictability may be the result of our not even having the concept of E, this
concept lying entirely outside the concepts in which our theory of

M is cou
ched.



[A

closely related issue
]

is the doctrine that the emergence of emergent properties cannot
be
explained
on the basis of the underlying processes, and that emergent properties are
not
reducible
to the basal conditions from which

they emerge.

Recentl
y
Boogerd et. al. (2005) echo
ed

this position.

The central question then is … whether there are properties of systems which cannot be
“deduced” from the behavior of
their
parts, together with a “complete knowledge” of the
arrangement of the system’s parts

and the properties they have in isolation or in other
simpler systems. Properties that are not deducible in this way we call strongly emergent
properties.

As a computer scientist, I don’t see

why predictability matter

or perhaps I
don’t understand what ph
ilosophers mean by it. Would one say that Microsoft
Word is predictable from quantum mechanics or even from logic gates? Is it r
e-
ductively explainable from those bases?

To explore this issue
Kim (1998) develop
ed

what he call
ed

a functional model
of reduct
ion
: a

higher level property E can be reduced to lower level properties B
if one can
find

mappings from B to E such that everything known about E can be
identified with what is known about B.


Kim claim
ed

this models allows him to conclude

that
all

higher
level (i.e.,
emergent) properties can be explained by mapping lower level properties to them.
In so doing he denie
d

the possibility of emergent properties that are not theoret
i-
cally predictable or reductively explainable.

(Kim also dismisses Nagel’s (1961
) bridge laws, which, generalized to inter
-
theoretic reduction have also been dismissed by Howard (2007).

I quote Howard
on this point below.
)

In my view
,

just as Fodor, Bedau, and Humphres go too far in their puzzl
e
ment
about emergence, Kim goes too far i
n his dismissal of it
.

Were I to attempt to

a
p-
ply
Kim’s

concept to the relationship between Microsoft
W
ord and logic gates, I
would
n’t know how to
start
. Certainly one can understand how Microsoft Word
has been built on top of logic gates. But
I doubt that

one could find the sort of
mapping between them that Kim requires.

From

a computer science perspe
c
tive, i
f
software development

were nothing more than a mapping of

lower level pheno
m-
ena to higher level phenomena
,
we wouldn’t need programmers. Software is
much
more complex than
the kind of

functional
mapping
that Kim describes
.


6


11/17/2013

Kim

says that

the reduction of an emergent property E to a basal
domain

B

co
n-
sists of three steps.

Step 1:
E must be
functionalized



that is, E must be construed, or reconstrued,

as a

property defined by its causal/nomic relations to other properties, specifically properties
in the reduction base
B
.

We can think of a functional definition of
E
over domain
B
as typically taking the
following (simplified) form:

Having
E
=
def

Having

some property
P
in
B
such that (i)
C
1
, . . . ,
C
n

cause
P
to be
instantiated, and (ii)
P
causes
F
1
, . . . ,
F
m

to be instantiated.

Step 2:
Find realizers of
E
in
B
. If the reduction, or reductive explanation, of a particular
instance of
E
in a given syste
m is wanted, find the particular realizing property
P
in virtue
of which
E
is instantiated on this occasion in this system; similarly, for classes of systems
b
e
longing to the same species or structure types.

Step 3:
Find a theory (at the level of
B
) that e
xplains how realizers of
E
perform the
causal task that is constitutive of
E
(i.e., the causal role specified in Step 1). Such a theory
may also explain other si
g
nificant causal/nomic relations in which
E
plays a role.

And that’s it.
Does it sound plausibl
e?
I can’t tell
. It would certainly be more
convincing
had

Kim demonstrated how it works on an instructive example
, say
Microsoft Word
.



Step 1.

I
f E were the properties of Microsoft Word and B were logic gates

how would I apply Step 1
?

How does Kim even k
now that Step 1 can be a
p-
plied?
How does Kim know that properties of Microsoft Word can be co
n-
strued or reconstrued as properties defined by their causal/nomic rel
a
tions to
properties relating to logic gates?
(I’m not sure I understand what he says is
need
ed.
T
hat’s the best I

ve been able to do.)
How does Kim know that there
are
C
1
, . . . ,
C
n

in
B
that cause
a
P in
B

that causes

F
1
, . . . ,
F
m

to be instant
i-
ated?
(
I don’t see where the F
i

are defined.
Am I right in supposing that

the
y

are intended to repr
esent E?
)

In th
e

concrete
case

of Microsoft Word
, what
are the P

and

the
C
1
, . . . ,
C
n
?
What even might the
y be?
If
the
F
1
, . . . ,
F
m

are intended to represent E
, what are the
F
1
, . . . ,
F
m

in the case of Micr
o
soft
Word?

I don’t know
where to begin
.



Ste
p 2.

What are the realizers of Microsoft Word in
B
?

Other than the P

and

the
C
1
, . . . ,
C
n

I don’t know what this means. Why is
this

a sep
a
rate step?



Step 3.

Assuming we get past steps 1 and 2, w
hat is the theory

at the gate
level that explains how the re
alizers

of Microsoft Word
perform the causal
task
s

that

constitute Microsoft Word
?

Isn’t this also step 1 again?
If not,
what is it?


I’ll admit that I’m confused about how this reduction is supposed to work. Of
course that doesn’t it doesn’t work. But I s
urely don’t understand it.
Pardon the
rant

to follow
, but w
hen computer scientists claim that some functiona
l
ity can be
realized

in software
, not only do we explain how that realization will work, we a
l-
so demonstrate that it work
s

by implementing it

and ru
nning it
.

Software that
7


11/17/2013

doesn’t run prove
s

no
thing. Yet s
o many of the philosophy papers I’ve
read

e
x-
press ideas at very
general

levels and leave it at that. There is rarely an a
t
tempt to
show that
the idea
s

work when applied even to simple example
s
.
I don
’t mean to
pick specifically on
Kim
, but this seems to be a typical case. The paper

makes no
effort

to show that
the proposed

reduction process actually works
. I would very
much like to see how it is used to reduce

a

property
often cited

as
emergent to
som
e widely understood basal domain.

A great many philosophy papers have titles like,

“Why X was wrong about Y”
and “Why Z was wrong about X being wrong about Y.”
Perhaps
there are

so many
errors

in philosophy papers

and some of these t
itles must reflect err
ors

is b
e-
cause claims are made but not
“executed.”

Again, pardon the rant.

How can one reduce a face to the clay from which it is molded?

To return the issue of reduction,
I like the following analogy. (I’ll provide
a
more
formal example later, but this an
alogy
serves, as Dennett likes to say, as a
n

intu
i-
tion pump
.) When a sculptor molds a face from clay is she really mapping prope
r-
ties of the clay onto properties of the face? I don’t think so. She is shaping the clay
to embody features of the face, but she

is not mapping
properties

of the clay, i.e.,
its molecular structure, onto facial attributes and characteristics
.
(It is even harder
for me to see what this might mean at a functional level.)
Clay is fairly homog
e-
neous, it’s properties the same throughout
. Which property would one say maps to
wri
n
kles and which to
ey
es?


Th
e

distinction between mapping properties and molding a shape
may seem
subtle, but I think it’s important. I
t’s certainly true that
to use clay to model a face,
the clay must have certain

properties
, including

the ability to be molded and to
hold a shape.
And t
hese properties
certainly
depend on its molecular stru
c
ture.
But
in using clay to model a face one is not mapping

clay’s molecular

structural
pro
p-
erties

to structural
properties
of t
he face. One is exploiting those structural
prope
r-
ties
to create a shape that resembles the face.
There is no useful

mapping from
properties of
clay molecules to facial features.

To use

Kim’s terms
,

I doubt that
anyone would

describe as

theoretica
lly

pr
e-
di
cta
ble

the process whereby

a sculptor causes
a face

to

appear
by

working

a
block of
unformed

clay.
Clay can be shaped into all sorts of things. Why would
one predict a face, much less a particular face? Or more to the point, how would
one
predict (or as
Bo
ogerd,
et. al.

say

deduce
)
the features and characteristics of a
particular face from the properties of clay?


To be sure
,

there are limits to what one can do with clay. One might describe
some of the limitations that clay imposes on the features and chara
cteristics that
one could model. For example, it may not be possible to model the
Pino
c
chio’s
face if
his

nose is so long that the clay cannot support it. But that’s not the same
thing as saying that one can deduce the actual features and characteristic of

a face
by examining the molecular structure of clay.


8


11/17/2013

Of course, it’s possible that I don’t understand what is meant by being able to
predict or deduce higher level prope
r
ties from lower level properties.

What about reductive expla
i
nability?
If a face has

been molded from clay, are
its

features reducible to the
properties

of the clay?
Ce
r
tainly
,

once the face exists,
one can
explain

how the clay has been used to create th
os
e
features
.
This clay
molecule is at this position in the cheek
; that one at that; t
he whole thing holds t
o-
gether because of the shape retaining properties of clay
; e
tc.
Is that sufficient?
Is
that reduction?
The “basal conditions” of the clay don’t seem to me to “explain”
the fe
a
tures of the face

at least not in any
useful

way.

But then

w
hat would

one be looking for
as

a
n

explana
tion of the face?
In what
terms would one want a face to be explained

by properties of clay
? What might an
explanation consist of?

I discuss this issue further below.

Again, perhaps I just don’t understand the te
rminology.

The problem of new concepts

Kim also
raises

the question of
what

emergent properties, after having emerged, can do


that is, how they are able to make
their special contributions to the ongoing processes of the world. It is obviously very
imp
ortant to the emergentists that emergent properties can be active participants in causal
processes involving the systems they characterize. …

We may, therefore, set forth the following as the fifth doctrine of emergentism:

The causal efficacy of the emerge
nts
:
Emergent properties have causal powers of their
own


novel causal powers irreducible to the causal powers of their basal constituents.

As Kim then argues,
granting emergent properties causal efficacy
leads to all
sorts of scientifically unacceptable
conclusions such as downward causation.

Y
et one could imagine

face recognition
software

(
I’m making it software
to
f
i-
nesse

the problem of
talking about how humans recognize faces
) that would ide
n-
tify
a

face in the clay as
being the likeness of

one person
rather than another.
Does
one want to grant
the face any sort

of causal power in that case?
To frame the
question in causal terms, imagine
(the
image of
)

the

face as operating on the sof
t-
ware, causing it to produce a result. This is similar to a person ope
rating on sof
t-
ware by clicking a button. Both the image and the button
-
click trigger the so
ftware
to act in certain ways.

To explore this issue

further

consider Chalmers


(2006)
definition of (strong)
emergence
.

Chalmers

pick
s

up on a point
raised in the
first
extract from Kim.
What happens if
an

emergent property

like being the image of
a

face

s
imply
doesn’t exist at the
lower

(
e.g
., clay)
level? Although not making that point expli
c-
itly, Chalmers put it this way.


[A] high
-
level phenomenon

is
strongly em
ergent
with respect to a low
-
level domain when
the high
-
level phenomenon arises from the low
-
level domain, but truths concerning that
phenomenon are not deducible even in principle from truths in the low level d
o
main.

9


11/17/2013

If an emergent conce
pt
does not exist
at a lower level, then truths about it ca
n-
not be deduced

from lower level tr
uths

at least

not

in the
way “deduced from”

is
being used here
.
Putnam

(1975)
explored

this question
by

asking

how one would
explain why a square peg can’t fit
into

a round hole (o
f incompatible size). Should
the explanation be based on quantum mechanics, or should it be based on geom
e-
try? Putnam argued for geometry, pointing out that any explanation based on
quantum mechanics can deal with

only

one

specific peg
,

one

specific hole
,
and
one specific orientation of the peg
and

the hole. A

geometrical explanation is
much more general and hence more useful.
Yet such a geometric explanation is
not deducible from

and in fact has not
h
ing to do with

quantum mechanics.

It is
geometry, not phy
sics.

Kim attempts to dispose of

the
problem of
concepts
that exist
at a higher level
but not

at the lower level

by arguing

that
such a

situation can

t arise.
He says that

many philosophers


want to argue
(a)

that

the existence of such emergent co
n-
cepts i
s established by

multipl
e

realiza
tion and
(b)

that such multiply realizable

emergent properties can play important roles in
the
special
(
higher
-
level
)

sciences
.

He di
s
pute
s

that claim

as follows
.

[If]

the “multiplicity” or “diversity” of realizers means an
ything, it must mean that these
realizers are causally and nomologically diverse. Unless two realizers of

[an emergent
property]

E

show significant causal/nomological diversity, there is no clear reason why
we should count them as two, not one. It follows
then that multiply realizable properties
are ipso facto causally and nomologically heterogeneous. This is especially obvious when
one reflects on the causal inheritance principle. All this points to the inescapable
conclusion that
E
, because of its causal/
nomic heterogeneity, is unfit to figure in laws, and
is thereby disqualified as a useful scientific property. On this approach, then, one could
protect
E
but not as a property with a role in scientific laws and explanations. You could
insist on the genuine

propertyhood of
E
as much as you like, but the victory would be
empty.

The conclusion, therefore, has to be this: as a significant scientific property,
E
has
been reduced


eliminatively.

I’m afraid that I don’t buy this argument. One problem is that it f
ocuses too
much on rebutting the significance of multiple realizability an
d

not enough on the
higher level abstraction
s
/regularit
ies

them
sel
ves
. A face
made of

clay is presum
a-
bly multiply realizable. But why does that matter? What matters is that the face
r
e-
sembles someone’s face, not that it could have been sculpted in many different
ways from many different materials.
I have more to say about multiple realiz
a
tion
below.

An example

that

demonstrates that multiple realization is not relevant

but that
higher

level concepts matter

is

the example in the paper’s abstract
: why does

a
steel
-
hulled

boat float. (This is similar to
Putnam’s peg
-
and
-
hole example
.)
My

answer is that a
steel
-
hulled

boat floats for two re
a
sons.

1.

The t
heory of buoyancy
tells us

that any o
bject will float if the weight of
the water it displaces is greater than its own weight, i.e., if its
overall ave
r-
age
de
n
sity is less than that of water.

10


11/17/2013

2.

It is possible to make virtually anything seem to have a density less than
that of water by using a t
rick.

Add some

enclosed
empty space
to the object
one wants to float. If the empty space is large enough
,

the combined vo
l-
ume of the empty space and the object to be floated will have an

overall
a
v-
erage
density
less than that of water.
A steel
-
hulled boat
consists of both
the materials that make up the boat along with
enough

empty space
to

di
s-
place more than their weight in water
.

Neither of these
reasons
ha
s

anything
to do with

the theory of steel

microstru
c-
ture
s

or
the microstructure
of any
of the
other m
aterial
s

of which a boat might be
made. It

s

n
o
t that th
e
se ideas cannot be derived from the theory of steel. It’s
si
m
ply that th
e
se
ideas
are independe
nt of steel
. To use a term often found in di
s-
cu
s
sions of emergence,
the
y

are autonomous. They
don’t exis
t at the level of
the
m
i
crostructure

theory of steel
. Yet added to the
microstru
c
ture
theory of steel,
these two ideas explain why the boat floats.

In Chalmer’s terms, these ideas are
used to express
truths about floating boats are not deducible, even in p
rinciple,
from truths about the microstructure of boat components.


It isn’t that the theory of steel micro
-
structures is not relevant.
As I said about
clay, w
hat is important about
the micro
-
structural properties of
steel is
that they
enable one to use

st
eel

to construct a waterproof skin

that

enclose
s

some empty
space
.
By analyzing steel’s microstructure one can determine
(a)

whether
steel’s

micro
-
structure blocks water

and (b)

whether steel can be produced in a shape that
encloses space
.
But

once it is e
stablished that steel can be used to construct a w
a-
ter
-
tight boat, steel’s micro
-
structural

properties have as li
t
tle to do with whether
the boat floats

as the
micro
-
structural
properties of clay have to do with

the fe
a-
tures of

a face.

The key is that ther
e are theories

that come into play at a higher
level
that are i
n
dependent of the properties of the lower
level
.

Is it surprising that there are laws that express regularities relat
ing

boats

to

w
a-
ter? Perhaps it is. But it seems to me that it’s the same so
rt of surprise that we feel
when we discover that there are laws (theorems) that express regularities about the
natural numbers. One of my favorite
s

is La
g
range’s theorem: every natural nu
m-
ber can be expressed as the sum of
four

or fewer squares.

Why shoul
d
that

be?

The natural numbers are simply zero and its successors. Why should they obey a
constraint like that? I
t seems that virtually any collection of

related

entities e
m-
bo
d
ies regularities that one might not at first expect. Why are things more co
n-
stra
ined than they seem? I don’t know.

It’s this sort of thing that strikes me as
mo
l
to mysterioso
.

Laws of this sort are

not a matter of derivability. Formally, any theory T that is
independent of some theory S is derivable from S. One imply ignores S and d
e-
r
ives T. Adding S to the derivation presumably does

no harm

as long a
s

S is not in
conflict with any of the assumptions
required

by T.
The more important point is
that T is
independent of
S
and
autonomous with r
e
spect to S.

11


11/17/2013

How does Kim deal with this sort
of higher level law?
In what to me is a co
n-
fusing passage Kim (2006
, pp 556
-
557
) seems
either to
say that irreducibility is
not meaningful

or to acknowledge th
at

emergent pro
p
erties

are

irreducible, but it’s
ok
.
(As I said, this is another passage that I d
on’t understand.)

If we know that X is reducible to Y, we know something interesting

and important about
the relationship between X and Y.
And if we also know that U is reducible to W, we
know something common that the pairs
<
X,Y
>

and
<
U,W
>

share

[namely
t
he reducibility
relationship]
.

I believe we can take reducibility as a genuine relation characterizing two
domains of properties, or two theories.

But this does not mean that irreducibility, namely
the
absence

of reducibility, is also a genuine and informa
tive relation. As has often been

observed, being red is a property but that does not mean that being nonred is also a
genuine property. There are too many diverse things that are nonred: green things, yellow
things, transparent things, numbers, atoms and m
olecules, thoughts and ideas,
propositions, and countless other sorts of things. The same applies to relations and their
negations. Number theory is irreducible to hydrodynamics and vice versa. Chemical
properties are irreducible to biological properties;
geological properties are irreducible to
economic properties and vice versa. If emergent properties are irreducible to their base
properties, does this instance of irreducibility have anything in common with those other
cases of irreducibility? The answer,

I believe, has to be “none”.

As I understand this passage, Kim is saying that irreduc
i
bility is not a well
-
defined relationship. So to say that number theory and hydrodynamics are mut
u
a
l-
ly irreducible is not saying
very much

because irreducibility is not
a well d
e
fined
relation
ship
. Yet since reducibility
is

presumably
a well defined relationship it’s
not clear to me why the statement

X
is irreducible

to
Y


cannot be understood as
saying that
“X is
reducible to Y” does not hold
.
Why isn’t this similar to

saying
that X is nonred means that the property red, which we presumably have a way of
d
e
fining, doesn’t apply to X?

Kim
’s

larger point is

that
no positive characterization of emergence has been
produced. Irreducibility, he says, is a negative condition.

He also says that supe
r-
venience is
a

negative condition
.
But

supervenience and irreducibility are
, he says,

the defining characteristics of emergence
.


[S
upervenience and irreducibility]

tell us what emergence is not; they do not tell us
anything

at leas
t, not much

about what it is.

I believe one pressing item on the
emergentist agenda is to provide an illuminating positive characterization of emergence.

I’m confused about where this leaves Kim.
He has written a lot about eme
r-
gence and reduction.
Does

he
believe that he has established that

s
upervenience
and irreducibility

don’t hold
? If so

then why does it matter that there are (in his
opinion) no positive conditions? Whatever they
might be
, they
presumably
won’t
hold either

since if
s
upervenience and irr
educibility don’t hold there can’t be an
instance of emergence
.

On the other hand, i
f
Kim
doesn’t believe that he has established that the neg
a-
tive conditions don’t hold

if he agrees
, as he apparently does,

that for example,
bio
l
ogy and chemistry are mutu
ally irreducible

then isn’t that all anyone has
asked? What’s left to discuss?
Biology and chemistry are mutually irreducible,
12


11/17/2013

and biology supervenes over chemistry. Isn’t that an example of what most people
mean by emergence? W
hat remains of the mystery.
As I said, I’m confused.

The Game of Life Turing machine.

To return to something that I understand better, h
ere’s the more formal exa
m
ple

I
promised earlier
.
In

Emergence Explained


(2006) I
discussed

the example of a
Turing machine implemented on a Game

of Life grid.
Such Turing machines are
subject to

in fact are the subject of

the theory of computability.
It may be that
there are multiple ways to implement a Turing machine using a Game of Life
framework. But it doesn’t matter whether there are or not.
What matters is that
c
omputability theory
applies to Turing m
a
chines no matter where or how they are
implemented, and computability theory
is independent of the Game of Life rules.

Turing and others developed c
omputability theory before Conway invented th
e
Game of Life. Its truths have nothing to do with the truths of the Game of Life.

As noted

above
, o
ne could argue that since
c
omputability theory was
derived

from scratch, it is derivable from the rules of the Game of Life.
It doesn’t depend
on the Game
of Life rules as a b
a
sis.
But that doesn’t seem to be what Kim,
Chalmers, or anyone else in this debate have in mind

when they speak of deri
v
a-
bility
.

C
omputability theory is

autonomous in a Game of Life world.
As a theory
characterizing a set of entities
(Turing machines) it neither depends on nor is in
conflict with the rules of the Game of Life. Because of that autonomy, i
f one uses
Game

of Life patterns to implement

Turing m
a
chine
s

there are things one can say
about that
those
Turing machine
s

that
they

compute particular function
s
, that
their

halting problem may be undecidable, etc.

that have nothing to do with
the
Game of Life rules.

Yet every Turing machine that runs on a Game of Life grid is completely d
e-
termined

by

(and reducible

to
)

the

Game of Lif
e rules.
But

like the reducibility of
facial features to molecules of clay,
reducibility

of

th
is

sort

is useless. One wants
to talk about Game of Life Turing machines at the Turing machine level and not at
the level of Game of Life grid cells.
This is simi
lar to my claim earlier that the
ability to describe how a particular face was modeled by a particular block of clay
is not useful. When speaking of faces one wants to be able to talk at the level of
faces, e.g., that the nose is not symmetric, that the ey
es are especially large, etc.
The same is true of Turing machines.
It’s a matter of being able to
say which

fun
c-
tions
are
being computed

and whether
the

halting problem is decidable. There

is
simply no vocabulary available at the Game of Life level to expr
ess those ideas.
I
don’t see how Kim’s
argument claiming that

new
concepts

are not eligible to
serve in scientific theories holds in these cases.

A Turing machine in a Game of Life world

is not all that different from
F
o
dor’s

(1974)
example of Gresham’s la
w

(that bad money drives out good)
.
Fodor denied

that Gresham’s law

can be derived from quantum mechanics.
As far
13


11/17/2013

as I know, he’s right. Gresham’s law

cannot be derived from quantum mechanics
b
e
cause it has nothing to do with quantum mechanics.

T
here is no
thing in Gres
h-
am’s law that depends on properties that one finds at the level of quantum m
e-
chanics. Like
c
omputability theory it is an abstraction that stands on its own.
It is
auton
o
mous.
In “The reductive blind spot”

(2008)

I discuss how the computer sc
i-
ence notion of level of abstraction clarifies these issues

including how the evol
u-
tio
n
ary process itself defines an autonomous level of a
b
straction.

It’s important to stress, though, that higher level entities don’t spring into being
de novo
. They are impl
emented by lower level entities. Game of Life patterns are
implemented by Game of Life rules. What happens when Game of Life patterns
interact depends on how the Game of Life rules play out. The “laws” describing
the interactions among Game of Life patter
ns depend entirely on Game of Life
rules. As I noted in “Emergence Explained” (2006) one can build a catalog of such
interactions. That catalog does not precede the rules. It results from the rules. Yet,
once that catalog is in place, one can use the inte
ractions to build constellations of
patterns and interactions, leading eventually to a Game of Life Turing machine.

The same is true of Gresham’s law. People exist only because we are material
beings who are implemented ultimately by fundamental particles.

But as dynamic
entities (see the section on entities), we are subject to

evolution pressures

which
reflect laws that express how the fate of dynamic entities is determined. This leads
ultimately to the impulse to hoard good money if bad money appears in t
he market
place. It’s a fairly long story, but it works in the material world only because ent
i-
ties of all levels (a)

are implemented by lower level entities and (b)

are subject to
laws
(as Chalmers says, truths)
that co
n
strain their interactions at their
own level.

Downward e
n
tailment

This perspective clarifies the issue of downward causation.
O
ne might wonder
why

a Game of Life Turing machine isn’t downwardly causing a particular grid
cell to go on at a particular time or why

Gresham’s law isn’t downwardl
y causing
an atom in a particular unit of good money to be put in storage somewhere.
Ne
i-
ther
of these

is an example of downward causation
. What is happening is that the
Game of Life grid cell is

part of the

implement
ation of

the Turing machine, and
the
ato
m is

part of the implementation of
the unit of good money. As long as
these
lower level elements

continue in th
eir

role
s

of implementing
the higher level ent
i-
ties, their

fate depends on the fate of the
higher level entity
. I
n


“Emergence E
x-
plained”

(2006)

I
called this
downward e
n
tailment
.

I was surprised to see that
Kim

(1999)
was

not bothered by this

even though he
thought of it as a kind

of
downward causation
.
A
s

what he called

diachr
onic
r
e-
flexive downward causation
, he

found

it unremarkable.

I fall fro
m the ladder and break my arm.

I walk to the kitchen for a drink of water and ten
seconds later, all my limbs and organs have been displaced from my study to the kitchen.
Sperry's bird flies into the blue yonder, and all of the bird's cells and molecules,

too, have
14


11/17/2013

gone yonder. It doesn't seem to me that these cases present us with any special mysteries
rooted in self
-
reflexivity, or that they show emergent causation to be something special
and unique. For consider Sperry's bird: for simplicity, think of

the bird's five constituent
parts, its head, torso, two wings, and the tail. For the bird to move from point
p
1

to point
p
2

i
s

for its five parts (together, undetached) to move from
p
1

to
p
2
. The whole bird is
at
p
1

at
t
1

and moving in a certain directi
on, and this causes, let us suppose, its tail to be
at
p
2

at
t
2
. There is nothing mysterious or incoherent about this. The cause
--

the bird's
being at
p
1

at
t
1

and moving in a certain way
--

includes its tail's being at
p
1

at
t
1

and
moving in a certain
way. But that's all right: we expect an object's state at a given time to
be an important causal factor for its state a short time later.

We must conclude then that … diachronic [reflexive downward causation] poses no
special problems but perhaps for th
at reason
[is]
rather unremarkable as a type of
causation.

As I understand it, Kim is arguing that because time passes, this sort of (appa
r-
ent?) downward causation is acceptable. I don’t follow that reasoning. It seems to
me that downward causation is susp
ect under any circumstances, whether time
passes or not.


To be fair, Kim was contrasting
diachronic

reflexive downward causation with
what he called
synchronic

reflexive downward causation, which he found una
c-
ceptable because it was circular. In his view
,

diachronic reflexive downward ca
u-
sation is not. But whether or not Kim’s argument works,
I believe that
my explic
a-
tion of it as downward e
n
tailment
provides a

better explanation
.

Downward entailment

also
explains why it’s not unreasonable to say that a
glider in
the G
ame of
L
ife

turns on


a particular cell

when it gets there
.
A glider
in the Game of Life is nothing.
It is a time
-
stepped sequence of patterns of on and
off grid cells. It

is epiphenomenal

over the application of the Game of Life rules
.
And

as we know, epiphenomena, by definition, are causally powe
r
less.
(Kim
1993) labels as epiphenomenal causation

and thereby dismissible

any appa
r
ent
causation associated with epiphenomena. F
rom the perspective of downward e
n-
tailment

I find epiphenomenal cau
sation perfectly reasonable. I see no problem in
saying

that an epiphenomena such as a glider can

cause


a grid cell to be turned
on.

At the level of gliders as entities, that’s what happens.
The cell is turned on

when
it becomes

part of the implementatio
n of the glider. That’s the only time that
dow
n
ward entailment makes sense
, when a lower level element participates in the
implement
a
tion of a higher level element
.

But this

raises another issue. Since a glider skitters across an unbounded nu
m-
ber of grid
cells, does it

super
vene

over
all of them

during

its lifetime

as one after
another they participate in its implementation
? Yes

it does

just as a biological
organism supervenes over a great many atoms and molecules over its lifetime
.

So
the fact that a bird
’s molecules move with the bird, depends on those molecules
being part of the bird’s implementation at that time. Since all biological organisms
apparently shed matter continually, only some of the bird’s molecules move all the
way with the bird. The ones
that don’t make it are left behind when they cease
15


11/17/2013

functioning as part of the bird’s implementation.
I discuss

the implications of

this
perspective
in the
s
e
c
tion

on
e
ntities
.

Lessons of Game of Life Turing machine
s

I
wish

to
propose the following

position
.



In a Game of Life world, the
Game of Life
rules
are analogous

to
the
fu
n-
damental
laws of
physics.

(This is the position taken by Dennett (1991).)



Turing machine
s

in a Game of Life world
are

emergent entit
ies

with eme
r-
gent properties.




Not only are Game o
f Life Turing machines emergent, they are objectively
identifiable through entropy considerations. They form distinguishable pa
t-
terns of a
c
tivities on the Game of Life grid.

Hence they are objectively r
e-
al

to the extent that anything in a Game of Life grid

is real.



Like everything else in a Game of Life world
,

Game of Life
Turing m
a-
chines are subject to and controlled by the Game of Life rules. Nothing
happens in a Game of Life world other than that the
Game of Life
rules are
applied and the cons
e
quences en
sue.



Computability theory is the

special science


of Game of Life Turing m
a-
chines.

It provides information about Game of Life Turing machines tha
t

is
not available at the level of the Game of Life rules. It would be perversely
unscientific not to study it
.



One could make a
further
case for studying computability theory in a
G
ame
of life world on the basis of information efficiency. In reviewing the si
g
ni
f-
icance of algorithmic information theory, Chaitin (2003) discusses how it
can be used to distinguish s
cience from data. Chaitin credits Leibniz with
first expressing this perspective in his
Discourse on Metaphy
s
ics
.

Leibniz observes that for any finite set of points there is a mathematical formula
that produces a curve that goes through them all, and it ca
n be
parameterized

so
that it passes through the points in the order that they were given and with a
constant speed. So this cannot give us a definition of what it means for a set of
points to obey a law. But if the formula is very simple, and the data is
very
complex, then that's a
real law
!

Algorithmic Information theory (AIT)

puts more meat on Leibniz's proposal
,
it
makes his ideas more precise by giving a precise defin
i
tion of complexity.

If one wants to do science, one wants the most powerful, i.e.,
the most
compact, expression of nature

s regularities that one can find. Algorithmic
information theory demonstrates that there is a way to make such a measure
of compactness precise.

I would take a similar position with respect to the boat example.

16


11/17/2013



Buoya
ncy

is the upward
force

on an object produced by
a

liquid or gas in
which
the object

is
(
fully or partially
)

immersed. The upward force
is
equal

to

the weight of liquid or gas displaced.



The theory of buoyancy

summarized
in the preceding bullet
abstracts t
he
notion of
buoyancy

in a
gas or
liquid within a gravitational field. It is p
a-
rameterized

i.e., abstracted

to capture regularities at an abstract level
and to be independent of any particular gravitational field, any particular
liquid

or gas
, and
any

part
icular
object whose buoyancy is at i
s
sue.



T
he theory of buoyancy is not reducible to any lower level theory. Since
I’m not a physicist, I may be on shaky ground here. I base this conclusion
on
the following from

Howard (2007)

in which he disputes Nagel
-
st
yle r
e-
ductionism. (Howard is a
Professor of the Philosophy of Science at Notre
Dame and Fellow of the American Physical Soc
i
ety
.)

[O]
ne is hard pressed to find a genuine example of inter
-
theoretic reduction outside
of mathematics. … That inter
-
theoretic re
duction might not be a helpful way to
think about inter
-
level relationships is perhaps best shown by pointing out that
everyone’s favorite example

of

a

putatively successful reduction

that

of
macroscopic thermodynamics to classical statistical mechanics

si
mply does not
work.



Are macroscopic thermodynamic phenomena, therefore, emergent with respect to
the mechanical behavior of the individual molecular and atomic constituents of the
systems of interest? Yes, if emergence means the failure of inter
-
theoreti
c
reduction. Is that an important fact? Yes, if our aim is to undermine dogmatic
reductionist prejudices or to unsettle the presupposition that physics, generally, is a
paradigmatically reductionist science. Otherwise, the significance of there not
being a

reduction of thermodynamics to statistical mechanics is not so clear.

Since m
acro
-
level buoyancy is
similar

to thermodynamics in that were

ei
-
ther

to be reduced
it

would be reduced to the statistical behavior of large
numbers of atoms or molecules
, I’m su
pposing that its reduction doesn’t
work either
.
This is not to say that buoyancy is a new force of nature, only
that
it is
meaningful

only

at a macro level.



The conclusion is that buoyancy applies to macro objects at a macro level.
Like computability theor
y it gives us information about macro objects that
cannot be expressed in the language available at the micro level. Buoyancy
theory lets us conclude that a certain steel
-
hulled boat will float.



This lets us conclude that the molecules in the steel hull w
ill not sink.
T
his
isn’t downward causation. It is downward entailment
from

the cons
e
quen
c-
es of macro phenomena to the micro
entities

that implement the macro o
b-
jects that are subject to the macro phenomena.

17


11/17/2013

Mystery solved?

So i
s there any mystery left

to
emergence
? I don’t think so. The basic picture is
that one can construct new things

(like Turing machines
, faces,

or steel
-
hulled
boats
)

by putting together existing things

(like Game of Life patterns
, clay,

or steel
plates
)
. Those new things
will conform
to laws or
have properties
(compu
t
ability
theory
,

facial characterization properties,
or buoyancy theory
)
that
may have

not
h-
ing (much) to do with the
laws governing the
components of
which
the new things

are built
.
The

parenthetical

“much” reflects

two qua
lific
a
tions
.

1.

The

new

higher level

laws
and properties
must be consistent with the lower
level laws. It is the lower level laws that enable the lower level elements to
implement the higher level elements.
If the higher level were not consistent
with the low
er level, the implementation would fail.
But
given

such

consi
s
-
tency
the higher level laws are autonomous

with respect to the lower level

and can be looked to when we want to understand how the higher level enti
-
ties fun
c
tion in the world.


2.

I
t matters whet
her it is possible to
implement

the
higher level entities

from
t
hose at the lower level. I
s it possible to
implement
a Turing machine using
Game of Life patterns
, a face from a block of clay,

or a boat
from
steel
plates
?
There is no automatic answer for th
at.
The answer depends on the
lower level
elements and the
capabilities
they offer
.
(It’s certainly not easy to
build a Turing machine using Game of Life patterns!)
But o
nce th
e impl
e-
mentation

barrier
has been
hurdle
d, the properties of the
lower level
com
p
o-
nents have little to do with the properties of the
higher level

con
struct
s

except

to limit the conditions under which the
implementation
succeeds.

A
steel
-
hulled boat

won’t float if the steel melts, and a Turing machine that r
e-
quires more space than a Ga
me of Life grid has available won’t run.

Non
-
reductive physicalism

metaphysical

As I understand it, the position I’m advocating has been described by Loewer

(2007a)
as non
-
reductive
physicalism

metaphysical. Loewer

c
haracterizes non
-
reductive physicalism (
NRP) as taking
either

of two p
o
sitions.

NRP is non
-
reductive in that it says that the special sciences involve laws, causal
relations, explanations, and so on that are, “in a certain sense”, irreducible to those of
physics and it is physicalist in “a ce
r
t
ain sense” since it says that everything is ultimately
constituted micro
-
physically and that the laws of microphysics are complete in the
domain of micro
-
physics. Fodor remarks that NRP is now (and has been since the 1970s)
“conventional wisdom” having rep
laced the reductionist conventional wisdom of previous
generations. Unfortunately, like much conventional wi
s
dom it is not so clear exactly what
it comes to.

Advocates of NRP differ on how to understand “irreducible” and
“physicalism.

The first way

which
I label “
NRP
M
” (for “non
-
reductive physicalism
Metaphysical”
)

understands the irreducibility of the special sciences as involving the
existence of kinds and laws that are metaphysically over and above the kinds and laws of
physics.
NRPM
endorses physicalis
m in so far as it claims that everything that exists is
18


11/17/2013

physically constituted and every special science nomological/causal transaction is
physically implemented.
[It]

doesn’t say that the fundamental laws of physics can be
overridden or are gappy. However

NRPM
[does say]

that special science laws are
autonomous from the laws of physics.

According to the other way of understanding NRP

which I label
NRPL
(nonreductive
physicalism
light
)

the irreducibility of the special sciences is not metaphysical but
mere
ly
conceptual and epistemological. According to
NRPL
the special sciences contain
vocabulary/concepts that are conceptually independent of the concepts/vocabulary of
physics.
NRPL
also allows that special sc
i
ences contain their own confirmation (and other
epistemic) relations that are independent of physics. A biologist may have evidence that a
biological generalization is lawful (think of the Mendelian laws) without having any idea
how this regularity is rendered lawful or implemented by fundamental laws o
f physics
even though the former is grounded in the latter.

However,
NRPL,
in contrast with
NRPM,
holds that the nomological structure of the world
is
completely specifiable by
fundamental physics. The special sciences don’t add to the nomological structur
e (as they
do according to
NRPM
) but rather they characterize aspects of the structure generated by
the fundamental physical laws that are especially salient to us and amenable to scientific
investigation in languages other than the language of physics.

NR
PM
and
NRPL
agree that the special sciences are conceptually, epistemologically, and
methodologically

autonomous/irreducible

to

physics

but

disagree

about

what
autonomy/irreducibility consists in and how it is to be explained.
NRPM
says that the
autonomy/i
rreducibility is metaphysical and seeks to explain the conceptual and
epistemological autonomy in terms of the existence of special science kinds and laws of
physics. If
NRPL
is true then the autonomy/irreducibility of the special sciences isn’t
explained
in terms of basic special science kinds and laws but must ultimately be

due to
facts and laws of micro
-
physics and to our epistemological situation in the world (which
it says is also due to the facts and laws of micro physics). The two views also disagree

about physicalism.
NRPL
is compatible with strong versions of physicalism on which all
truths, including those of the special sciences, hold in virtue of facts and laws of
fundamental physics.
NRPM
rejects this strong claim since it says there are facts a
bout
kinds and laws of special sciences that are independent of physics but it is compatible
with t
o
ken physicalism

… .

I believe that my position is NRPM since I claim that higher level entities “r
e-
a
l
ly” exist

and that they are constrained by laws that
ar
e independent of phy
s
ics
.

See the section on entities for a further discussion of why I claim that higher level
ent
i
ties really exist.

A few
more
words about multiple realization

M
ultiple realizability seems to be central to
much of
the discussion of emerg
ence.
But I don’t see why. As the example of the Game of Life Turing m
a
chine showed
(at least I think it showed it), multiple realiza
bility

is not relevant to

whether

hig
h-
er level laws

are autonomous
. So
I don’t understand why

multiple
realizabi
l
ity
play
s

such a central role in discussions of emergence and reducibi
l
ity?

Furthermore, it seems to me that most of the

claimed examples

of

multiple r
e
a
l-
ization are misleading

at best
. My fundamental point will be that multiple r
e
aliz
a-
bility does not apply to natur
ally occurring entities.

Since multiple
realizabi
l
ity
19


11/17/2013

comes up in
the
discussion of the non
-
reducibility of mind, and since mind (as far
as we know)
is
a property only of naturally occurring entities, my a
r
gument
will
be

that multiple
realizabi
l
ity
is misu
sed in those discussion.

Putnam’s (1975)
defines

multiple realizability
in terms of functional isomo
r-
phism.

[T]wo systems are functionally isomorphic if there is an isomorphism that makes both of
them models for the same … theory. …

[Two] system can have

quite different constitutions [e.g. they might be made of
copper,
cheese, or soul
] and be functionally isomorphic.

Since Putnam is speaking at the level of abstract systems and models, I have no
complaint about this

statement
.
Putnam was applying concepts

from computability
theory. I agree that multiple realization occurs in computing machines. Two co
m-
pu
t
ing devices may implement the same function in radically different ways.



Problems begin to arise when one
looks more carefully at

what is being
claimed

as being multiply realized
, what Putnam calls the theory for which two
systems both serve as models
. The easiest thing
s

to realize in multiple ways are
the input/output behaviors of systems. If two systems have well
-
defined interfaces
,

an
d

if the (pr
e
suma
bly symbolic) inputs and outputs
that traverse

those interfaces
can

be mapped to each other, then the claim that the two
systems

multiply impl
e-
ment the same i
n
put/output behavior seems to be fairly straightforward. Or at least
it
does

on a symbolic level.

I
n real
-
life i
t is often very important how long it takes
a
system

to convert an input into an output. If we want to take time into consider
a-
tion when we say that two
systems
implement the same behaviors in di
f
ferent
ways, the problem becomes significantly

harder. But let’s ignore that i
s
sue.

A
n alternative

claim may be that two
systems
implement the same comput
a-
tional process in multiple ways. That is, it may be claimed that the two
systems
perform the same internal computations, i.e. that they
each
have
a set of states that
can be mapped to each other and that the state transitions that they perform are
identical under that mapping. That’s a reasonable way of
specifying

condition
s

under which two
systems
may be said to be computationally equivalent. If tw
o
such
systems
are composed of different materials, e.
g.
, one is
made of
silicon
chips and the other is
made of
cogs and wheels

(or as Putnam says, copper, cheese
or soul)
, then it makes sense to say that the two
systems
implement the same co
m-
putation in d
ifferent ways.

Clearly this second
version of multiple realizability
r
e-
quirement is significantly
more stringent that the first
.

Multiple
realizability
is often used in arguing that psychological theories are
multiply realized. Bickle (2008) defines mult
iple r
e
alizability as follows.

In the philosophy of mind, the multiple realizability thesis contends that a single mental
kind (property, state, event) can be realized by many distinct physical kinds. A common
example is pain. Many philosophers have asser
ted that a wide variety of physical
properties, states, or events, sharing no features in common at that level of description,
can all realize the same pain.

20


11/17/2013

Since Bickle uses the term
pain
, a term referring to subjective experience, he is
presumably requi
ring that multiple realization occur
s

at the internal state
-
transition level and not at the behavioral level. After all, pain isn’t defined at
the

behavioral level
; it is
by definition

a subjective experience
. But it seems

presum
p-
tuous

to me for anyone to
claim that we know what sort
s

of
psychological states
an organism that is capable of feeling pain has and what
state transitions occur
within
such an

organism when it is experiencing pain. Subjective experience is
still one of the great areas of ignorance.

Given that we know so little about subje
c-
tive experience and how it is implemented, h
ow could
anyone

argue that two o
r-
ganisms
have isomorphic states that they
traverse

in the same way

when they are
feeling pain?

I understand that if one could establish
(
a)

that two organisms
had isomorphic
pain states and state transitions but (b)

were implementing th
em
differently, one
would have a case for multiple
realization
. But I can’t get past the step of esta
b-
lishing what the in
ternal
subjective states of an organ
ism

in

pain

are

much
less
establishing that two organisms have isomorphic internal subjective
pain
states
and state trans
i
tions.

Besides, doesn’t this become an empirical question? It will take a lot of empir
i-
cal investigation to establish what states and

state transitions are associated with
pain. Once we know that, if we ever do, it will be much easier to co
m
pare the
states and state transitions of different organisms and see whether they are is
o-
morphic. But ultimately this seems like an empirical que
sti
on. I don’t see how it
has
come
to be accepted as
the foundation stone of much of current day philos
o-
phy.

Even if one retreated to the behavioral definition of “the same” I still have a
problem. To say that two entities realize the same model, requires th
at there be a
model.
It seems to me that a problem arises when the notion that a theory can be
used to describe

a system is turned around and understood to mean that a system
realizes a theory. The problem is that when one says that a system realizes a th
e
o-
ry, the theory comes first.

When we as human designers build an artifact, the
theory does come first

the
idea precedes the object. This, of course is approximate. All design
, natural and
man
-
made

is iterative.
But in simple approximate terms, h
uman desig
ners visua
l-
ize a result and then build a system
to realize that vision
.

T
hat’s certainly not what
happens in nature. Nature doesn’t visualize

and then implement
. It simply strikes
out in random directions. If something succeeds, it
persists
; otherwise it
d
isa
p-
pears
.

I realize that asking whether this isn’t an empirical question is

in some sense
putting the issue backwards. I gather that the point is that one may come up with
an abstract model for pain states and then (somehow) establish that different o
r-
gan
isms are implementing that model. I have a number of difficulties with that a
p-
proach. For one thing, we don’t have a model for pain states and pain state trans
i-
21


11/17/2013

tions, and it’s not clear to me that we will be able to come up with one in the a
b-
stract. It see
ms more likely to me that we will develop a model of pain and pain
state transitions by examining how actual organisms work. Secondly, even if did
develop an abstract model of pain states and pain state transitions, how would we
validate it in the abstract
? Why would we have confidence in such a model before
determining whether it really described how at least one organism functioned. Fu
r-
thermore, I suspect that any abstract model we developed without validating it
against a real organism would be too gener
al to be of much use.

To explain why I’d like to focus on externally observable behavior rather than
internal states. That way we will have something more visible than pain to talk
about. Let’s
take flying as an example.
Bats, birds, and bees
all
fly.
We
could pr
e-
sumably build a model of flying whose features were the features that bats, birds,
and bees have in common when they fly: they suspend themselves in the air and
travel from place to place while doing so.

Since bats, birds, and bees all realize
tha
t model, have we demonstrated
multiple realization of flying?

One could argue that we have, but I don’t see it as particularly useful. My sense
is that bats, birds, and bees came to their ability to fly through significantly diffe
r-
ent evolutionary paths.
Since the common ancestor of birds, bats, and bees did not
fly, the ability to fly must have developed independently in each group. So what
does this tell us? Birds, bats, and bees fly very differently. But because flying is
can provide an evolutionary adv
antage, it developed a number of different times.
It did so because we all live in a sea of air.

Of course in some sense it is. But how useful is it to say that bats, birds, and
bees multiply realize flying? Does that make flying any more real than it wou
ld be
if only bats (or birds or bees) flew? I don’t see why it does. Flying is a relationship
between the flier and its enviro
n
ment.

We may look at naturally occurring phenomena

like flying

and create a
predicate to describe: flies(x). We may then find a
number of things to which that
predicate as we define it applies. flies(birds), flies(bees), flies(bats), …. But that
doesn’t mean that nature started with the predicate and implemented it in multiple
ways. Nature doesn’t do that. The fact that birds, bees
, and bats all fly is a cons
e-
quence of the fact that they all exist in an ocean o
f

air and that flying is a useful
way to get around in that environment.

On the other hand, when human beings create things, we generally start with a
specification

or at lea
st an idea

which we then implement. Once we have a
specification, it’s often clear that there are many ways to implement it. Putman’s
original example of multiple realization was of a computing device, a human cre
a-
tion that is describe by a specification.

But naturally occurring entities don’t have specifications. There is no specific
a-
tion of a bee or a bat. As human beings we can find similarities among groups of
entities and we can find ways of grouping entities together, typically by reference
22


11/17/2013

to their
genomes. But that isn’t a specification created by nature. It’s just the way
it turned out.

That’s why biology is so messy. We tend to think in terms of clean divisions: a
person is either a male or a female for example. But we now know that it nowhere
nea
r that clear. A person may have two X chromosomes but may also have gene
switches that failed to switch on some of the male
-
property producing genes. Such
a person looks externally like a female. According to Fausto
-
Sterling (2000),

The concept of interse
xuality is rooted in the very ideas of male and female. In the
idealized, Platonic, biological world, human beings are divided into two kinds: a perfectly
dimorphic species. Males have an X and a Y chromosome, testes, a penis and all of the
appropriate int
ernal plumbing for delivering urine and semen to the outside world. They
also have well
-
known secondary sexual characteristics, including a muscular build and
facial hair. Women have two X chromosomes, ovaries, all of the internal plumbing to
transport uri
ne and ova to the outside world, a system to support pregnancy and fetal
development, as well as a variety of recognizable seco
n
dary sexual characteristics.

That idealized story papers over many obvious caveats: some women have facial hair,
some men have
none; some women speak with deep voices, some men veritably squeak.
Less well known is the fact that, on close inspection, absolute dimorphism disintegrates
even at the level of basic biology. Chromosomes, hormones, the internal sex structures,
the gonads
and the external genitalia all vary more than most people realize. Those born
outside of the Platonic dimorphic mold are called intersexuals. …

Consider, for instance, the gene for congenital adrenal hyperplasia (CAH). When the
CAH gene is inherited from b
oth parents, it leads to a baby with masculinized external
genitalia who possesses two X chromosomes and the internal reproductive organs of a
potentially fertile woman.

If different organisms have evolved different mechanisms to experience pain
(whatever
it really means to say that), that doesn’t make pain an abstraction that
they have both impl
e
mented. This is similar to the argument that even though
birds, bees, and bats have evolved ways to fly, it doesn’t make sense to say that
“flying” as an abstracti
on implemented by nature is multiply implemented. Each
of the three evolved ways to fly because they all live in an environment that i
n-
cludes flyable air and they (evolutionarily) figured out how to propel themselves
through it. The same can be said for do
lphin fins and flounder fins. They are both
used for swimming, but they are not multiple realizations of an abstract ability to
swim.

In both of these cases (flying and swimming) the specification, to the extent
that there is one, is given by the environm
ent (air and water) and the usefulness of
being able to propel oneself through it. We may call what bats, birds, and bees do
by the same name, and we may call what dolphins and flounder do by the same
name, but these are only our names, not a formal abstra
ction that nature has co
n-
tracted to implement. The point is that these activities exist at a higher level of a
b-
straction than the level of their implementation, but that’s not the same thing as
saying that they’re the same from one implementation to anothe
r.


23


11/17/2013

A significant difference between specifications that can be implemented in
multiple ways and the philosophical notion of multiple realizability is that specif
i-
cations are intended to describe systems from the outside. Multiple realiz
a
bility is
not cle
ar about what it is trying to do. If what is being multiply realized is a spec
i-
fication, then it is the same. But sometimes that isn’t so clear. Pain, for e
x
ample, is
not a specification of anything. So it isn’t clear what it means for it to be multiply
re
alized. Even being a mousetrap isn’t very clearly specified since the i
n
terface is
not well spelled out. In CS one describes multiple implementations of an interface.
In multiple realizability the interface that is claimed to be multiply rea
l
ized

if it
is
even an interface that is being claimed to be multiply r
e
alize

is generally not
clearly defined. .

Multiple Realization is a flawed concept with respect to naturally occurring e
n-
tities.
MR occurs only when there is a specification to multiply realize. But

there
are no specifications in naturally occurring entities.

Nonetheless, properties converge to similar results because they must solve the
same environmental problems, e.g., flying. Also because they often d
e
rive from a
common starting point. They e
x
is
t in the same environment.


What is this saying? Do we really know enough about how minds work to talk
about “a single mental kind (property, state, event)”? How can one construct an
argument about something when we know so little about that subject matter
?
Worse, how can one build a philosophical position on the basis of such an arg
u-
ment? Do we have any confidence that we can all agree on what is a mental kind
and what isn’t? I can’t imagine that we do. So how can one then talk about whet
h-
er they are multi
ply reali
z
able? Besides, even if we eventually do agree about
what we are talking about, isn’t the question of whether it is multiply reali
z
able an
empirical question and not a theoretical one? What reason do we have for belie
v-
ing that a wide variety of ph
ysical properties, etc. can all realize the same pain?
First of all, what do we mean by “the same pain”? Who is to say that one pain is
the same as another

even if we allow that two pains may not nece
s
sarily be two
pains but may possibly be “the same pain”
? Besides, might that not differ from
person to person? One person may be more self
-
aware than another. The la
t
ter
may not be able to distinguish a pin in the finger from a knife cut on the toe. A
n-
other may.

What about visual illusions? Is a visual illusi
on an example of multiply realized
vision? Or what if I prick you with a pin and then prick you in exactly the same
place with a different pin. Is that multiply realized pain? If so, so what? If it’s not,
then what about a pin and a needle? What about a p
in and a needle but the pricks
are a micro
-
millimeter separate from each other? What if one person can actually
tell the difference and another can’t? What if I modify the example so that two i
n-
ternal pains feel exactly the same, i.e., stimulate in exactly

the same way the po
r-
tion of the brain that is responsible for our subjective experience of pain? Are they
24


11/17/2013

an example of multiply realized pain? If not, if two different portions of the brain
have to feel exactly the same for one to say that pain is multip
ly realized, what if
of two people one can distinguish one from the other and a second can’t? So
what? What if our brains were such that stimulating two different portions pr
o-
duced the same subjective experience? So what? That seems to me to the sort of
mi
stake that appeals to multiple realizability continually makes. It takes two di
f-
ferent things and generalizes them in a way that claims to make them the same and
then argues that since they are the same, some other conclusion can be drawn. But
that’s not v
alid. How can one build a philosophical position on the basis of som
e-
thing so loosely defined? Yet people have been writing about this sort of thing for
decades

and apparently no one has said that it’s all based on words whose mea
n-
ing we barely understand.

This isn’t to say that multiple realization isn’t possible. Given any non
-
trivial
computer program, I can guarantee I can produce a different computer program
with the same input output characteristics. So the program is multiply realized. So
what? On the

other hand, the two programs probably won’t run in exactly the
same time. Certainly the two programs won’t produce the same instruction trace.



[Computer Scientists have a definition of types, which are an operational ve
r-
sion of kinds.]

Kind
: collection

of entities that cannot be distinguished one from another.
Then more broadly, collection of entities with labels, like the same genome
--

but
not using arbitrary attributes as labels, whatever that means. Even hydrogen has
the label one proton and one ele
ctron but any number of neutrons. All protons are
i
n
distinguishable. Nature does not make kinds "on order." The kinds are resultant,
not made to order.


Fodor, “Special Sciences: Still Autonomous After All These Years,”
Noûs
,
Vol. 31, Supplement: Philosoph
ical Perspectives, 11, Mind, Causation, and World,
(1997), pp. 149
-
163.

p. 159. Kim is wrong about what’s wrong with jade. … Kim is also wrong about the
analogy between jade and pain. … Kim’s picture seems to be of the philosopher
impartially weighing the
rival claims of empirical generality and ontological
transparency, and serenely finding in favor of the latter. But that picture won’t do. Here,
for once, metaphysics actually ma
t
ters.

p. 154. Kim almost sees this [whether it matters whether a property is

disjunctive or
multiply realizable] in the closing sections of his paper. But then he gets it wrong: fatally
in my view.

What about dirigibles, airplanes, missiles, and hang gliders. These multiple r
e-
alizations of flying? One could argue that they are: we

often use that term when
talking about what they do. But what value do we get out of doing so? What too
25


11/17/2013

many of these papers seem to do is to attribute an abstract reality to what is co
m-
mon among them. Now I want to attribute a reality to the capability o
f propelling
oneself through air. But that doesn’t mean that two ways of doing that are part of a
common abstraction. That’s an oversimplification, that seems to have been lost.

The bigger problem seems to me to be the looseness of thought

which is
strang
e because philosophy is specifically supposed be about thinking things out
carefully. For example, at the start of “Still autonomous” Fodor says that Kim is
prepared to agree (at least for the sake of argument) that (1)

psychological states
are multiply r
ealized (MR) and (2)

MR states are ipso facto unsuitable for redu
c-
tion.

How can one be so carefree in talking about mental constructs? Do we really
know enough about psychological states that we feel comfortable using intu
i
tion
about them as the basis for

a careful philosophical analysis of what the world is
like?

But what about causation?

The discussion so far has taken a very naïve and intuitive view of causation: som
e-
thing can be said to cause something else. We took Kim’s requirement of causal
effici
ency at face value.

The real question concerns the sorts of things that can be
built
.
Shalizi (1998)
put it nicely.


Instead of asking how
to

carve Nature at
its

joints, we ask why Nature has those particular
joints

or
even has joints at all

and is not (to

continue with the metaphor) a single
undifferentiated hunk of inharmoniously quivering meat
.


Some
where
,

as

quantum field theory meets general relativity and atoms and void merge
into one another,
the fundamental

rules of the game

are defined
. But

the res
t of the
observable, exploitable order in the universe

benzene molecules,
PV = nRT,

snowflakes, cyclonic storms, kittens, cats, young love, middle
-
aged remorse, financial
euphoria accompanied with acute gullibility, prevaricating candidates for public offi
ce,
tapeworms, jet
-
lag, and unfolding cherry blossoms

where do all these regularities come
from? Call this "emergence" if you like
. I
t's a fine
-
sounding word, and brings to mind
southwestern creation myths in an oddly apt way
. But it’s just
a
label
; i
t mar
ks the
mystery without explaining anything.
.
[The preceding includes some
copy

editing that
does not change the sense.]

2.

The f
our + 1 categories of emergen
t entities

Kim suggests that the following are the central claims about emergence.

1. Emergence of com
plex higher
-
level entities
: Systems with a higher
-
level of complexity
emerge from the coming together of lower
-
level entities in new structural
configurations (the new “relatedness” of these entities).

26


11/17/2013

2.
Emergence of higher
-
level properties
: All propertie
s of highe
r
level entities arise out of
the properties and relations that characterize their constituent parts. Some properties of
these higher, complex systems are “emergent”, and the rest merely “resultant”.

3.
The unpredictability of emergent properties
:

Emergent properties are not predictable
from exhaustive information concerning their “basal conditions”. In contrast, resultant
properties are predictable from lower
-
level information.

4.
The unexplainability/irreducibility of emergent properties
: Eme
r
gen
t properties, unlike
those that are merely resultant, are neither explainable nor reducible in terms of their
basal conditions.

5.
The causal efficacy of the emergents
: Emergent properties have causal powers of their
own


novel causal powers irreducible t
o the causal powers of their basal constituents.

[We saw this one earlier.]



Naturally occurring

Human Designed

Static

Atom, molecule, solar
system
, …

q慢汥l bo慴a hous攬 捡rI

sh楰I g敯
J
s瑡瑩tn慲y s慴a

汩瑥Ⱐ



Dynamic

Hurricane, biological o
r-
ganism
, bi
ological

group
,


䑥獩an敤 so捩慬c group
such 慳a 愠 捯un瑲y go

敲nmen琬t a 捯rpor慴楯nI 愠
pok敲 捬cb

瑨e
sh楰 of
qh敳敵sI g敯
J
s瑡t楯n慲y

t
敬汩瑥e




Entity
: persistent material pattern. But exclude flames, explosions, etc. by
some means.

Besides the previ
ous, computers offer
an experimental entity laboratory, an

environment within which entities can be created without having to worry about
energy or resources.

In all cases the entities are emergent
through the
implement
a-
tion of
persistent patterns of exis
ting entities.

In naturally occurring emergence the abstraction that is implemented is typ
i
ca
l-
ly messy (quote Zimmer’s description of DNA).

It is not designed, but usually it
survives if it is sufficiently stable or powerful.

In human designed emergence th
e
abstraction typically comes first
. Then we attempt to implement it

with var
y
ing
degrees of success.

Philosophical functionalism focuses on the second of these. It
is always looking at abstract specifications and then noting that those a
b
stract
specificat
ions can be implemented in any of a number of ways. That’s fine, but in
focusing exclusively on the abstraction
-
to
-
implementation side, it ignores the i
m-
plementation
-
to
-
abstraction side

and in so doing misses the source from which
abstraction
springs
.

27


11/17/2013

In
Section xx I discuss the various types of entities and point out that naturally
occurring entities are not designed by nature in anything like the way man
-
made
entities are designed. When we design artifacts, we generally have some idea what
we want the ar
tifact to do. To a greater or lesser extent, we conceptualize the a
b-
straction

and often write it down as a specification

before we create a design
that we hope will realize it. Obv
i
ously this is an exaggeration. Most artifacts have
their specifications cha
nged in the course of their development as we learn more
about what we are building. But the more important point is that for the most part
when we design something we have in mind what we want the designed entity to
do. Since nature doesn’t have a mind, i
t can’t have anything in it. Nature’s designs
realize abstractions by chance. The ones that realize useful abstractions persist.
The others don’t. So there is a fundamental difference between how emergence
works for naturally and ma
n
made entities.

3.

Laws fr
om a Computer Science perspe
c
tive

Loewer summarizes what he says is Fodor’s view of the place of the special sc
i-
ences.

[Each] special science taxonomizes nature into natural kinds in terms of its own
proprietary vocabulary. What makes a special science a

science
is that it contains lawful
regularities stated in its proprietary vocabulary that ground explanations and
counterfactuals. [What] makes a special science regularity
lawful
is a fact that is
irreducible to the laws and facts of fundamental physics
(and other special sciences). That
is, the lawfulness of special science regularities is a fact about the world as basic as and
independent of the lawfulness of the laws of fundamental physics. Fodor’s view can be
illustrated with the help of a souped up v
ersion of Laplace’s demon. The demon knows all
the physical facts obtaining at all times and all the fundamental dynamical laws of
physics, has perfect computational powers and also a “translation” manual connecting
special science and physical vocabularie
s. The demon is thus able to tell which micro
physical situations correspond to, for example, a philosophy conference and is able to
determine which generalizations about philosophy conferences are true and which are
false. It can do the same for all the s
pecial science. It will also be able to tell which
special science regularities hold under counterfactual initial conditions and so which hold
in all physically possible worlds (i.e. all the worlds at which the fundamental laws of
physics obtain). But on F
odor’s view the demon
will not
be able to discern which
regularities are laws.

Because of this “blindness” the demon will be missing those
counterfactuals and explanations that are underwritten by special science laws and so will
not have an understanding
of special science phenomena. Although the demon will be
able to predict and explain the motions of elementary particles (or whatever entities are
physically fundamental) from the state of the universe at any time and so could have
predicted the stock mark
et crash of 1929 it will not understand why it crashed. To do that
it would need to know ec
o
nomics.

As the extract from Loewer indicates, philosophers
are quite concerned, e.g.,
(Carroll 2008),

about when regularities
represent

are the result of laws and
when
they are accidental.
T
he issue
is often posed in terms of the criteria to require of
28


11/17/2013

statements
for them to be considered laws
.
In the context of emergence and redu
c-
tionism,
Howard suggests that the appropriate focus is not on statements but about
mo
d
els.

[A
] chief

disadvantage of
]
thinking about the relationship between different levels of
description in terms of

intertheoretic reduction



is the
restriction to theories
represented
syntactically as sets of statements or propositions
, central among wh
ich are statements of
laws, for there is reason to think that many important scienti
fic theories

evolution is an
often cited example

are not best understood in this way.
[An alternative is]

a
semantic
view of theories, whereupon a theory
is conceived as a
set of models
.

A computer science perspective doesn’t face that problem. A computer is unde
r-
stood to have operations that transform one state of the computer into a
n
other
state. The operations are the “laws” that hold in a computer universe.
A
n

easy
-
to
-
un
derstand example is the Game of Life. The rules that characterize wh
ich

cells
will
be born, which will
live
,

which will
die
constitute

the laws of a Game of Life
universe. There is no issue about discovering laws or of wondering whether there
are laws that

bring about particular regularities. The laws are known, and that’s all
there is to it. The only thing that happens on a Game of Life grid is that cells go on
and off accor
d
ing to the Game of Life rules or laws.

The more important question is whether the

laws can be used to accomplish
certain results. For example, when Conway first created the Game of Life he
didn’t know whether there was a way of arranging initial conditions so that the
number of live cells would increase indefinitely. Of course that que
stion was soon
answered with the invention of what’s come to be called a glider gun, a configur
a-
tion of cells that traverse a cycle in the course of which a glider

is generated
. Each
time around the cycle a new glider is
created
, thereby showing that the n
u
m
ber of
live cells
on a grid
can be made to increase indefinitely.

A related question is to determine just what
a
particular sequence of
trans
i
tion
s
will do.
T
here was
once some
hope that the field of program verification would
develop

to

the point

that
one could formally prove that a sequence of
transition
s
w
ou
l
d

produce a given result. That goal has been found to be beyond our reach

at least for now. In general one cannot always guarantee the result to be produced
by a sequence of
transition
s.
There are

both theoretical and practical problems.
Some questions about sequences of transitions are simply undecidable. Others are
so complex that it is infeasible to attempt to answer them.

Furthermore, computer programs no longer consist of single sequences of
tra
n-
sition
s. Multiple asynchronous sequences of
transition
s occur. The results pr
o-
duced by their interaction is even more difficult to formalize than the results pr
o-
duced by a single sequence of
transition
s. Nonetheless, one has confidence that
there is al
ways a mechanism that explains in terms of fundamental computer o
p
e
r-
ations how a particular result was produced.

Depending on the model, the laws can be higher or lower level. If one writes a
program using the basic instructions of the computer (which no
one does), it is
those operations that constitute the laws. If one write a program in a higher level
29


11/17/2013

programming language (such as Java or C++), it is the primitive operations avai
l-
able in those languages that constitute the laws.

Most computer programs ma
ke use of libraries. When that’s the case, the o
p
e
r-
ations provides by programs in the library become part of the laws.

How does this relate to the philosophical issue of laws of nature. The phil
o-
s
o
phical issue tends to focus on statements

which of them re
present laws. In a
computer world, the laws are known; statements that describe them are for the
convenience of the reader, not as a way to pin them down. What pins down the
laws in a computer world is the computer model itself.

So what if we used that ap
proach to characterized laws of nature? What if we
developed computer models that are intended to reflect our understanding of how
nature works? The laws that we write into the model are the intended laws. But
t
hose laws are not expressed
as

statements in
predicate calculus; they are expre
s-
sions in whichever programming language we used to build our model.

4.

Examples of emergence

Bedau and Humphreys

One of the best ways to get a feel for emergence is to consider widely cited core examples
of apparent emergent

phenomena. The examples involve a surprising variety of cases.
One group concerns certain properties of physical systems. For example, the liquidity and
transparency of water sometimes are said to emerge from the properties of oxygen and
hydrogen in struc
tured collections of water molecules. As another example, if a magnet
(specifically a ferromagnet) is heated gradually, it abruptly loses its magnetism at a
specific temperature

the Curie point. This is an example of physical phase transitions,
which often

are viewed as key examples of emergence. A third example involves the
shape of a sand pile. As grains of sand are added successively to the top of the pile, the
pile forms a conical shape with a characteristic slope, and successive small and large
avalanc
hes of sand play an important role in preserving that shape. The characteristic
sand pile slope is said to emerge from the interactions among the grains of sand and
gravity.

Life itself is one of the most common sources of examples of apparent emergence. O
ne
simple case is the relationship between a living organism and the molecules that
constitute it at a given moment. In some sense the organism is just those molecules, but
those same molecules would not constitute an organism if they were rearranged in an
y of
a wide variety of ways, so the living organism seems to emerge from the molecules.
Furthermore, developmental processes of individual organisms are said to involve the
emergence of more mature morphology. A multicellular frog embryo emerges from a
sin
gle
-
celled zygote, a tadpole emerges from this embryo, and eventually a frog emerges
from the tadpole. In addition, evolutionary processes shaping biological lineages also are
said to involve eme
r
gence. A complex, highly differentiated biosphere has emerge
d over
billions of years from what was originally a vastly simpler and much more uniform array
of early life forms. The mind is a rich source of potential examples of emergence. Our
mental lives consist of an autonomous, coherent flow of mental states (bel
iefs, desires,
30


11/17/2013

memories, fears, hopes, etc.). These, we presume, somehow emerge out of the swarm of
biochemical and electrical activity involving our neurons and central nervous system.

A final group of examples concerns the collective behavior of human ag
ents. The origin
and spread of a teenage fad, such as the sudden popularity of a particular hairstyle, can be
represented formally in ways similar to a physical phase transition, and so seem to
involve emergence. Such phenomena often informally are said to

exhibit ‘‘tipping
points.’’ Another kind of case is demonstrated in a massive traffic jam spontaneously
emerging from the motions of individual cars controlled by individual human agents as
the density of cars on the highway passes a critical threshold. I
t is interesting to speculate
about whether the mechanisms b
e
hind such phenomena are essentially the same as those
behind certain purely physical phenomena, such as the jamming of granular media in
constricted cha
n
nels. …

5.

One version of emergence

Do the g
lider gun as an example of the interaction of higher level e
n
tities.

The version of emergence that I want to formulate differs from most others in that
it includes an explicit intermediate construct. In many formulations of emergence
one imagines that low
er
-
level functionality is somehow directly (or mysteriously)
transformed into higher
-
level functionality. This approach leads to the sort of mu
l-
ti
-
determinant d
i
lemma that Kim has repeatedly pointed out.

My alternative is to suggest that lower level functi
onality (and ent
i
ties) may
create compound entities and that those compound entities may often have prope
r-
ties and capabilities that are autonomous from those at the lower level. As an e
x-
ample consider an object that floats in water. An object floats when
the water it
displaces weighs at least as much as the object itself. Some objects are naturally
buoyant because they are made of materials that are less dense than w
a
ter. But
let’s consider only objects that are made of materials that are more dense than w
a-
ter but that still float

objects with a concave shape that exclude water from an
empty interior space and use that interior space as part of their displacement vo
l-
ume.

How does one relate the properties of the (lower level) materials of which such
an obje
ct is made to the object’s ability to float? Since the construction materials
are denser than water, one can’t map any sort of lower level buoyancy to the
buoyancy of the floating object. So the ability to float is not in any traditional
sense directly red
ucible to lower level

properties.

The object floats (a)

because of
its shape and (b)

because of the ability of the materials of which it is made to e
x-
clude water from its interior.

The ability of such an object to float is, I would claim emergent. It is a

property
of the object (as a higher level construct), and that ability is not directly attribu
t
a-
ble to properties of the materials of which it is composed. That is, there is not
h
ing
about the component materials that would suggest that a construct made of

those
31


11/17/2013

materials will float. Some definitions

of emergence require that emergent prope
r-
ties be not be deducible, “even in principle” from lower
-
level properties.

Chalmers put it this way.

We can say that a high
-
level phenomen
on is
strongly eme
r
gent
with

respect to a low
-
level
domain when the high
-
level phenomenon arises from the low
-
level domain, but truths
concerning that phenomenon are not
deducible
eve
n in pri
n
ciple from truths in the low
-
leve
l domain
.

It’s not clear to me what it means to say that th
at some truths are not deducible
(even in principle) from other truths. Chalmers explains in a footnote that he
means “
that strong emergence requires that high
-
level truths are not concept
u
ally
or metaphysically necessitated by low
-
level truths.”

I’m afrai
d I still don’t unde
r-
stand. Is the ability of our example object to float deducible from truths about the
materials of which it is made along with truths about water, buoyancy, etc.? N
a-
ively I would think so. After all the object does float

and we can expl
ain why.
So it must be deducible from truths about its components, etc.

On the other hand, in order for our object to float it had to have been co
n
struc
t-
ed in such a way that it enclosed space that was used to displace water. Is the co
n-
cept of such a cons
truction among the truths of the lower level, or is it avai
l
able
for use in a derivation of the higher level truth that the object does float? If not,
then the ability of the object to float is presumably not deducible (even in princ
i-
ple) from the lower le
vel truths.

Another way to approach this issue is to note that the physics of buoyancy is
independent of the truths about the lower level domain. So in that sense also once
can’t derive the ability of the object to float from truths about the lower level
d
o-
main alone. One must add the physics of buoyancy, which has nothing to do with
the lower level domain.

For either or both of the two reasons just examined (that the construction of the
object and the physics of buoyancy are not part of the lower level) I

suspect

but
obviously don’t know

that Chalmers would say that the ability of the object to
float isn’t deducible from lower level domain truths. Consequently it satisfies
Chalmer’s definition of (strongly) emergent.

Does the ability of the object to float

satisfy Kim’s requirements for eme
r-
gence: supervenience and functional irreducibility? Certainly the object supe
r-
venes on its components. Change the components and the object changes. So it
seems to me that supervenience is not an issue. What about functi
onal irreduc
i
bi
l-
ity? The question of functional irreducibility seems to me to raise the same i
s
sues
as those raised by Chalmer’s requirement of non
-
deducibility. What does it mean
for something not to be functionally reducible to something else? Kim doesn’
t
provide a definition. So it’s hard for me to say. I would guess that it means that
there is no composition of lower level functions that are equivalent to the ta
r
get
higher level function. Kim
(2006)
gives as an example that “
Number theory is i
r-
reducible

to hydrodynamics and vice versa.” Since both number theory and h
y-
32


11/17/2013

drodynamics are independent, it’s not clear to me why they are not mutually r
e-
ducible. After all each can be constructed
ab initio
. So it is no harder to co
n
struct
each theory if one starts
by assuming the other.
Perhaps what is intended by r
e
du
c-
ible in this context is that one theory is dependent on the other. Just as nu
m
ber
theory doesn’t depend on hydrodynamics the physics of buoyancy does not d
e-
pend on the properties of materials. So in t
hat sense the ability of the object to
float satisfies Kim’s requirements for emergence.

Like Kim and Chalmers, Howard (2007) also suggests that irreducibility and
supervenience are central to emergence. Howard is more explicit with respect to
what he mean
s by irreducibility. He adopt Nagel’s (1961) formulation as follows.

Intertheoretic reduction
is a
logical
relationship between theories. In the classic
formulation owing to Ernest Nagel, theory
T
B
, assumed correctly to describe or explain
phenomena at le
vel
B,
reduces to theory
T
A
, assumed correctly to describe or explain
phenomena at level
A
, if and only if the primitive terms in the vocabulary of
T
B
are
definable via the primitive terms of
T
A
and the postulates of
T
B
are deductive
consequences of the po
stulates of
T
A
.

As normally formulated, this definition of reduction
assumes a
syntactic
view of theories as sets of stat
e
ments or propositions.

Howard goes on to say.

Thinking about the relationship between different levels of description in terms of
inte
rtheoretic reduction has the advantage of clarity, for while it might prove difficult
actually to determine whether a postulate at level
B
is derivable from the postulates of
level
A
…, we at least know what we mean by derivability and definability as relat
ionships
between syntactic objects like terms and statements, since we know by what rules we are
to judge. The chief disadvantage of this way of thinking about inter
-
level relationships is
that one is hard pressed to find a genuine example of intertheoreti
c reduction outside of
mathematics, so to assert emergence as a denial of reduction is to assert something trivial
and uninteresting.

That inter
-
theoretic reduction might not be a helpful way to think about inter
-
level
relationships is perhaps best shown
by pointing out that everyone’s favorite example of a
putatively successful reduction

that of macroscopic thermodynamics to classical
statistical mechanics

simply does not work. Recall what is required for reduction: the
definability of terms and the deriv
ability of laws. Concede the former in this instance

as
with the definition of temperature via mean kinetic energy

and focus on the latter.
Foremost among the thermodynamic laws that must be derivable from statistical
mechanical postulates is the second la
w, which asserts the exceptionless evolution of
closed non
-
equilibrium systems from states of lower to states of higher entropy. Providing
a statistical mechanical grounding of the second law was Boltzmann’s paramount aim in
the latter part of the nineteen
th century.

Did he su
c
ceed?

The answer is no. For one thing, what Boltzmann derived was not the deterministic
second law of thermodynamics but a statistical simulacrum of that law, according to
which closed nonequilibrium systems are at best highly likely
to evolve from states of
lower to states of higher entropy. More importantly, even this statistical simulacrum of
the second law is derived not from mechanical first principles alone but from those
conjoined to what was early termed the
ergodic

hypothesis
,

which asserts that, regardless
of its initial state, an isolated system will eventually visit every one of its microstates
compatible with relevant macroscopic constraints, like confinement to a surface of
constant energy in its phase space. The ergodic h
ypothesis can be given comparably
opaque equivalent formulations, such as the assertion of the equality of time and
33


11/17/2013

ensemble averages, but the work that it does in the foundations of statistical mechanics is
clear: The theory being a statistical one, it mu
st work with averages. The ergodic
hypothesis makes the averages come out right. The crucial fact is, however, that for all
but a few cases special cases or for highly idealized circu
m
stances, the ergodic hypothesis
and its kin cannot be derived from mecha
nical first principles. On the contrary, we can
demonstrate non
-
ergodic behavior for a large class of more realistic mo
d
els.

It was of course my intent that the ability of the object to float be considered
emergent. I selected this example exactly because
I wanted a case of emergence
that was easy to talk about. I hope that the preceding discussion has accomplished
that o
b
jective.

Even though there are many ways to build an object that has the ability to float,
this isn’t a matter of multi
-
realization. Whet
her or not there are multiple ways to
realize the ability to float is not relevant. What is relevant is that lower
-
level el
e-
ments combined to form a higher
-
level entity that had that new property.

6.

Why are philosophers so often wrong
?

In reading many of the

philosophical papers about emergence and abstraction I’ve
been struck by how difficult it seems for philosophy as a discipline to reach co
n-
clusions. I can understand why some issues are timeless: what’s a good life; how
should people behave; etc. But as I

understand it much of philosophy is an attempt
to clarify terms and issues. I would have thought that such a process would resolve
itself over a reasonable period.
Also, it seems that philosophers continually find
holes in each other’s arguments. That see
ms especially distressing. Philosophers
are smart people. Do they really make so many mistakes? Also, it’s usually not
that the holes are minor problems; they are at least claimed to be significant
enough to destroy entire arguments. It strikes me that one

possible reason for this
is that many philosophical arguments are couched in terms that are so removed
from empirical verification that it’s quite easy to make mistakes. In software we
don’t have that problem. We make plenty of mistakes. They are called b
ugs. But
because our arguments (our creations) must actually run and produce results, the
problems generally show up. This section lists some of the examples.

References

Abbott, Russ

(
2006
)

“Emergence explained,”
Complexity
, Sep/Oct, 2006, (12, 1)
13
-
26
.

Pr
e
print:

http://cs.calstatela.edu/wiki/images/9/95/Emergence_Explained
-
_Abstractions.pdf

Abbott, Russ (2007) “Bits don’t have error bars,”
Workshop on Enginee
ring and Philos
o-
phy
, October 2007. To be included in the selected papers from the confe
r
ence.
http://cs.calstatela.edu/wiki/images/1/1c/Bits_don’t_have_error_bars.doc
.


34


11/17/2013

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