I haven’t
done a “Physicists say the darndest things” post in a while.  People usually ask me to write one up every
time a Lawrence Krauss, Sean Carroll, or Stephen Hawking (well, lately not
Hawking) publishes a new “gee whiz” pop philosophy book masquerading as a pop
science book.  I find the genre extremely
boring.  It’s always the same dreary,
sophomoric PBS-level stuff: We’re all
just heaps of particles, but golly this really increases rather than decreases
the wonder of it all, and here’s some half-baked amateur metaphysics and life
lessons that even hardcore materialist philosophers would regard as fallacious
and banal.
  The only variable is
whether the crap philosophy in these $30 time wasters is coupled with clueless
arrogance (cough, Krauss) or at least
presented with some humility. 

In Brian
Greene’s case we have someone who seems a pleasant enough fellow.  But his new book
Until
the End of Time
nevertheless exhibits the usual foibles of the
genre.  I’ll focus here on what he says
about the place of the human mind in the physical universe (the topic of
chapter 5).  The basic metaphysical
assumption is a crude reductionism: All that really exists, we are assured, are
basic particles governed by mathematical laws. 
Hence consciousness, free will, etc. must somehow either be reduced
without remainder to these, or eliminated from our picture of reality.  The problem Greene wants to solve in the
chapter is to explain how this program can most plausibly be carried out.

Physics ain’t all that

There are
three main difficulties with Greene’s solution to the problem.  First, the solution is a non-starter, because
second, he doesn’t understand the problem in the first place.  But third, it doesn’t matter, because the
reductionistic assumption that creates the problem isn’t true anyway.

Let’s start
with that last point.  Greene insists
that the “evidence” supports his basic reductionist assumption.  In fact, the “evidence” does no such thing,
and the assumption is false.  Greene
himself inadvertently hints at the reason why. 
For one thing, he writes:

The art of science, of which Newton
was the master, lies in making judicious simplifications that render problems
tractable while retaining enough of their
essence to ensure that
the conclusions drawn are relevant.  The
challenge is that simplifications effective for one class of problems can be
less so for others.  Model the planets as
solid balls and you can work out their trajectories with ease and
precision.  Model your head as a solid
ball and the insights into the nature
of mind will be less
enlightening.  But to jettison
unproductive approximations and lay bare the
inner workings of a
system containing as many particles as the brain – a laudable goal – would
require mastering a level of complexity fantastically beyond the reach of
today’s most sophisticated mathematical and computational methods
. (p. 117)

Very
true.  The problem, though, is that
Greene seems to think that if we did
have a complete mathematical description of the particles that make up a brain,
then we would have captured all there is to the brain.  What he fails to see is that such a description would itself be just as
much a simplifying abstraction as modeling your head as a solid ball would be
.  True, it would be a model that captures much more of the mathematical structure of
the brain, but the point is that it would still be capturing only mathematical structure and nothing
else. 

But is there
anything more to matter than its
mathematical structure?  Of course there
is, because there is no such thing as mathematical structure without some concrete
reality that has the structure.  Mathematical structure by itself is a mere abstraction from concrete reality.  A description of the brain in terms of
nothing more than particles governed by mathematical laws, no matter how complex this description, can no more give you a complete description of the brain than
spherical geometry can give you a complete description of a planet or a basketball.  And Greene himself inadvertently admits this
too.  He writes:

I don’t know what mass is.  I don’t know what electric charge is.  What I do know is that mass produces and
responds to a gravitational force, and electric charge
produces and responds to an electromagnetic force.  So while I can’t tell you what these features
of particles
are, I can tell you what these features do… For gravitational and electromagnetic
influences, any concern that substituting action and response for an intrinsic
definition amounts to an intellectual sleight of
hand is, for most researchers, alleviated by the spectacularly accurate predictions we can extract from our mathematical
theories of these two forces
. (p. 133)

What Greene
is acknowledging here is that the methods of physics don’t capture the
intrinsic nature of phenomena, but only those relations between phenomena
susceptible of mathematically precise description.  Hence physics simply doesn’t tell us
everything there is to know even about
the material world
(let alone anything beyond the material world).  As I have noted many times, this is a point
that used to be often commented upon by scientists and philosophers (Poincaré,
Duhem, Russell, Eddington, et al.) and has in recent years been getting renewed
attention in academic philosophy. 

What Greene
doesn’t see is that the point completely undermines his basic reductionist
assumption.  Why should we assume that what
is real must be reducible to physics’ mathematical description of basic
particles, if we already know that that description doesn’t capture every
aspect of reality in the first place?

Greene also
acknowledges that we need what he calls “nested stories” about different
“layers of reality” – not just the story about what is going on at the level of
fundamental particles governed by mathematical laws, but also “higher-level
accounts” couched in language about learning, creativity, thinking,
deliberating, and other concepts that have no applicability at the level of
laws and particles (pp. 154-55).  Readers
of Daniel Dennett will recognize in this a warmed over variation on his theory
of the different “stances” we might take toward phenomena (namely the physical stance, the design stance, and the intentional stance).

All the
same, Greene insists on giving the lower-level story about particles and laws a
privileged status, and treating any part of a higher-level story that cannot be
reformulated in lower-level terms as merely a useful fiction.  But why should we agree with that?  For one thing, the thesis that the
higher-level stories are just convenient fictions faces the same problem that
all versions of anti-realism do, namely that it is hard to see how these
“stories” could work so well, and indeed be as practically indispensable as
they are, if they weren’t true.  (This is
known as a “no miracles” argument in the philosophy of science literature.)

For another
thing, why should we not turn the tables and hold instead that it is the higher-level story that tells us the truth
about the world, whereas the lower-level story is merely a simplifying
abstraction that is useful for certain purposes (such as technological ones)
but that leaves out much of concrete reality and thus is not strictly
true?  This is essentially the view taken
by anti-reductionist philosophers of science like Nancy Cartwright.

Greene
claims that the “evidence” provided by the successful predictions made using
the laws of physics supports his reductionist position, but it does nothing of
the kind.  After all, as Greene himself
happily acknowledges, there are no laws that allow us rigorously to predict the
behavior of systems conceived of as
dogs, cats, basketballs, dollar bills, human beings, etc.  We have to abstract out all that is
distinctive of these things qua biological, cultural, economic, etc. phenomena
and describe them instead in the simplifying terms of physics, and then we will get rigorous predictions
(though only of those aspects of their behavior that are reflected in the
simplifying description). 

So, all that
Greene is entitled to say is that mathematically precise laws accurately
describe the behavior of systems modeled at a high enough level of abstraction
to be characterizable in terms of mathematically precise laws.  Which, though not entirely unimpressive
(since it could have turned out that the laws failed no matter how abstractly we modeled the phenomena) is still not
nearly as impressive as Greene needs it to be. 
In particular, it hardly shows that there is no more to physical reality
than is captured by the laws and abstract models.

Greene’s
fallacy is like that of someone who says that, since a map is enormously useful
for getting around a certain bit of terrain, predicting what you’ll see when
you reach this or that part of it, etc., it follows that there is nothing more
to the terrain that what is captured by the map.  As Alfred
Korzybski once
said, “the map is not the territory.”  If
only more physicists were capable of seeing what a crackpot linguist could!

Anyway,
whether you agree with me or with Greene, here’s the thing: The dispute is not a scientific one but a
philosophical one
.  As I have argued
at length in Aristotle’s
Revenge
and elsewhere, the compelling arguments are all on the
anti-reductionist side.  But even if we
anti-reductionists were wrong about that, Greene has said nothing to show that
we are.  Greene thinks he has solidly
established a metaphysical result by drawing it out of physics, but all he has actually done is to read a dubious
and unsupported metaphysical claim into
physics. 

Physics cannot solve the problem, because
it creates the problem

Let’s move
on to the second difficulty, which is that Greene does not understand the
problem he is trying to solve.  To be
fair, he does at least see that there is
a problem facing anyone who wants to insist on the kind of reductionism he
favors while also affirming the
reality of conscious experience.  He
appeals to arguments like Thomas
Nagel’s “bat argument”
and Frank
Jackson’s “knowledge argument”
to illustrate the problem, and he
realizes that they can’t be waved away after the fashion of the village Reddit
materialist. 

All the
same, he fails to see the depth of the problem, and in particular fails to see
that the methods of physics are precisely
what generate the problem in the first place
, so that it is clueless to
think (as Greene does) that the problem can be resolved by further application
of those methods.  Moreover, some of the
writers Greene cites make this point themselves.

Here’s the
basic idea.  The founders of modern
physics put at the center of the scientific conception of the world the idea
that matter should be characterized in terms of quantifiable primary qualities
alone – size, shape, motion, position, etc. 
Irreducibly qualitative features
like color, sound, heat, cold, and the like were to be treated as secondary
qualities, reflecting the way we experience the world, but not how the world
really is in itself.  To be more precise,
for purposes of physics, colors were to be redefined
in terms of surface reflectance properties, sounds in terms of compression
waves, temperature in terms of molecular motion, etc.  Hence, if by “red” we mean such-and-such a
reflectance property, then we can say that a certain apple is red; but if instead
we mean by “red” the way red looks to
everyday experience, then that exists only in the conscious observer, and not
in the apple itself.  If by “heat” we
mean such-and-such a pattern of molecular motion, then we can say that the
water in a certain bathtub is hot; but if instead we mean by “heat” the way heat feels in everyday
experience, then that too exists only in the consciousness of the
observer.  And so on for other secondary
qualities (as Greene himself recounts at p. 139).

Though the
details of the story have changed over the centuries, what has persisted to the
present day is a tendency to treat so-called secondary qualities as merely the
qualia of our conscious experience of the material world, rather than anything
to be found in the material world itself. 
They are simply not the kind of thing that can be captured by the purely
quantitative, mathematical language to which physics confines its description
of matter.  And the problem is that this
conception of matter entails a kind of dualism. 
For if these qualities do not exist in the material world, then they
must not exist in the brain, which is part of the material world.  Yet if they do exist in the mind, then the mind must not be identical
with the brain or with any other part of the material world.

Like so many
other superficial materialists, Greene thinks the problem merely has to do with
its being intuitively difficult to
see how conscious experiences could be material.  No, the problem is much deeper than that – it
is that modern physics essentially defines
the physical world in a way that entails that consciousness is non-physical
.   The problem has less to do with consciousness than with matter as physics conceives of it.

Descartes
and his followers saw this implication, and that
(rather than intuition, religious prejudice, or some other anticlimactic
rationale) is why they judged consciousness to be immaterial.  Indeed, the basic problem was recognized by
the ancient atomist Democritus, who is, ironically, quoted by Greene
himself.  In particular, Greene cites the
Intellect’s side in an exchange Democritus imagined the Intellect having with
the Senses:

Intellect:
Color is by convention, sweet by convention, bitter by convention; in truth there
are but atoms and the void.

What Greene
does not quote is the retort that Democritus put into the mouth of the Senses:

Senses: Wretched
mind, from us you are taking the evidence by which you would overthrow us?  Your victory is your own fall.

Democritus’s
point is that if the atomist says both
that atoms are all that exist and
that color, sweetness, etc. and the other qualities of conscious experience are
not to be found in the atoms, then we have a paradox.  For conscious experience is what provides the
empirical evidence on which the atomist account is itself based!  The atomist thus seems unable to fit the very
evidence his theory relies on into the picture of the world the theory
describes.  Democritus was intellectually
honest enough to take note of this problem, though we don’t know how he tried
to resolve it, if he did.

Erwin
Schrödinger noted
that the same problem afflicts modern physics, which takes for granted a
conception of matter that is in the relevant respect like that of the ancient
atomists (though of course in other respects it is very different).  And Nagel’s argument in “What Is It Like to
Be a Bat?” makes the same point.  The way
Nagel puts it is that since physics works with a conception of matter as
essentially objective (in the sense
of being independent of any particular observer’s point of view), it cannot
incorporate into its picture of reality the subjectivity
of conscious experience (which is precisely tied
to
the point of view of the observer).

For this
reason, Nagel and other contemporary philosophers of mind like David Chalmers
have argued that consciousness cannot be explained in physical terms unless physics revises its conception of
matter.  Greene considers Chalmers’
version of this idea, but replies that there is no “convincing evidence” for
such a thesis (p. 135).  But the reason
he doesn’t see the evidence is, as Orwell would say, because it’s right in
front of his nose.  It is there in physics’ own conception of matter, which
excludes consciousness from the material world precisely by allowing into that
world only what can be described in the language of mathematics.

Nobody in here but us particles

Greene is
keen on saying that we are all just “collections of particles,” and goes on at
length about how he is himself just a collection of particles (pp.
156-57).  That we seem to be more than
that is, he suggests, just an illusion.  Here
again he borrows from Dennett, by way of neuroscientist Michael Graziano.  Just as, according to the primary/secondary
quality story, we project onto external reality properties that aren’t really
there (such as the red of a Ferrari, in Greene’s example), so too do we project
onto the internal world of the brain a stream of conscious thoughts and
experiences that aren’t really there. 
Greene writes:

You continuously create a schematic
mental representation of your own state of mind.  If you are looking at the red Ferrari, not
only do you create a schematic representation of the car, you also create a
schematic representation of your Ferrari-focused attention.  All the features you bind together to
represent the Ferrari are augmented by an additional quality summarizing your
own mental focus…

[This] is the heart of why conscious
experience seems to float unmoored in the mind.  When the brain’s penchant for simplified

schematic representations is applied to itself, to its own
attention, the resulting description ignores the very physical
processes responsible for that attention.  That is why thoughts and sensations
seem ethereal, as if they come from nowhere, as if they hover in our heads
. (pp. 140-1)

Now, I
certainly understand the attractions of this “higher-order representation” sort
of view.  I once defended a version of it
myself, in my doctoral dissertation during my naturalist days.  But it’s hopeless.  Here are some of the problems with it.

First, it just
keeps kicking the problem back a stage, ad
infinitum
.  Again, the view starts
with the primary/secondary quality thesis that redness, heat, etc. as common
sense understands such qualities don’t exist in the external material world but
only in our representations of it, as the qualia of conscious experience.  This opens up the problem that if these
qualities don’t exist in external material things like the Ferrari, then they
can’t exist in the brain either,
since it too is material.  Greene’s answer
to this problem is to say: “OK, then not only do they not exist in the Ferrari,
but they don’t exist in the brain’s representation
of the Ferrari; instead they exist in the brain’s higher-order representation of the brain’s representation of the
Ferrari!”  And of course, that just moves
the pea under another shell, because higher-order representations in the brain
are just as material as first-order representations in the brain.  And if Greene deals with this problem by appealing to some third-order representation, then the problem will just pop up again
there, like the proverbial whack-a-mole
(if I can introduce yet another analogy).

Second, it’s
actually worse than that, because the notion of “representation” is itself a mental notion which, like
consciousness, cannot be assimilated to the conception of matter physics has
inherited from the early moderns.  On
that conception, matter is just colorless, odorless, soundless, tasteless, and meaningless particles in motion.  Matter on its own does not stand for, point to, refer to, or represent anything; it lacks intentionality or “directedness toward”
any object beyond itself (to put the point using the standard technical philosophical
jargon).  The early moderns’ conception
of matter took intentionality no less than qualia to exist only in the mind’s
awareness of the physical world and not in the physical world itself – which,
again, is why they took the modern conception of matter to entail the
immateriality of the mind.

So, if
Greene is beholden to this conception of matter, he owes us an explanation of
how intentionality or representational content can arise in a material world
thus understood.  But his “explanation”
essentially amounts to saying: “Representation arises in a world that doesn’t
already include it once the brain starts representing itself as the sort of
thing that has representations in it.”  That’s
like Feynman’s
example of the painter
who claimed he could make yellow paint by mixing only
red and white paint, as long as he also added some yellow paint to the mix somewhere
along the way.  The painter can make
yellow paint where it doesn’t yet exist – but only if there’s already some
yellow paint lying around.  And the brain
on Greene’s account can make mental representations where they don’t already
exist – but only if there are some mental representations lying around.  If you don’t see the fallacy here, then you
might be qualified to write a pop science bestseller.

Third, Greene’s
position entails a self-defeating skepticism. 
Not only do we have no genuine access to the external world – but only to our inner representations of it – it turns
out we don’t really have access even to those inner representations of
the external world either, but only to representations of them.  And in fact (if we
follow this out consistently), we don’t have access even to those, but only to yet higher-order representations ad infinitum.  So how do we know that anything is real, including
Greene’s own account of what is really going on?
 

Even professional
philosophers like Dennett who peddle these sorts of views are
unable to solve the problems facing them
. 
Poor Greene isn’t even aware that the problems exist.  And yet, though less obnoxious than a blowhard
like Krauss, he is no less confident in his absurd conclusions. 

It can be
charming when a child pretends that he is a cloud, or a boulder, or a lion, or
even – I suppose – a collection of particles. 
It’s considerably less charming when a grown man does it, and when he is
a grown man with a Ph.D. and a tenured position at Columbia, it’s downright
embarrassing.  But you need only turn on
the news to see that otherwise intelligent people believing ever more
ridiculous things on the basis of ever more convoluted sophistries is the story
of our age.  There is a crucial but
widely overlooked lesson here.  When your
basic assumptions are unsound, greater intelligence by no means guarantees that
you will come to see this.  On the contrary,
sometimes you will end up only more
hardened in error than a less intelligent person would be, because you will be
able to come up with subtler fallacies and cleverer self-deceptions.

Related
posts:

Greene
on Nozick on nothing

Why
are (some) physicists so bad at philosophy?

Not
understanding nothing

A
gigantic book royalty check from nothing

Scientists should tell
Lawrence Krauss to shut up already

Carroll
on laws and causation

Mad
scientists

Source link

Leave a Reply

Your email address will not be published. Required fields are marked *