Reply to Henry Stapp's message of Thu, 2 Nov 1995.
 
This message is a response to Stapp's reply to my commenary on his
article, ``Why classical mechanics cannot accomodated consciousness but
quantum mechanics can''.
 
I want to first try to say what it seems to me is main point that Stapp
wants to urge, which I don't think came out clearly in his original article.
Then I would like to make a brief reply.
 
In my commentary on Stapp's original article, I described the traditional
mind/body problem as arising from a set of four propositions all of which
have powerful motivations but which are inconsistent with one another.  I
argued that the main point that Stapp seemed to be urging in his article,
that vectors in a quantum description of a system encode information about
the whole system, while that is not true of a classical description of a
system, did not show that quantum mechanics was inconsistent with any of the
propositions that give rise to the puzzle, and that any solution to the
puzzle open to a quantum theorist is equally open to a classical theorist,
so that the difference that Stapp identified was irrelevant to the mind/body
problem.
 
In his reply to this, Stapp identifies another difference between quantum
and classical mechanics, and argues that it is what is crucial to seeing why
quantum mechanics helps us to solve the mind/body problem while classical
mechnics cannot.
 
In particular, Stapp says:
 
> The essential difference between quantum mechanics and classical
> mechanics is that the fundamental constituents in classical mechanics
> are "objects", but the fundamental constituents in quantum mechanics
> are the "wave function" (i.e., the state vector) and the "events".
> The wave function represents not "objects", but "propensities for events
> to occur", and the basic realities are these "events" themselves.
 
 
And he says:
 
> This fundamental difference between classical mechanics and quantum
> mechanics undermines Ludwig's discussion of the motivation for
> proposition (2).
 
My proposition (2) was that the fundamental constituents of objects do not
have mental properties.
 
A few remarks.  First, in the above, Stapp does not say that quantum theory
entails that the fundamental constituents of objects have mental
properties.  Rather, his point seems to be that quantum theory undermines
the reasons I offered to think that the fundamental constituents of objects
have mental properties.  Second, he now cites as the feature of quantum
theory which has this effect that "the fundamental constituents in quantum
mechanics are the 'wave function' and the 'events'."
 
In the following, I will want to ask whether these claims are correct.
 
Before doing that, however, I want to say something about what position it
now appears that Stapp is endorsing on the mind/body problem, since it is
not the position I had assumed he was adopting, namely, emergentism.  While
Stapp, at some points in his reply, seems only to be claiming that quantum
mechanics undermines the reasons for holding my proposition (2), it is clear
in fact that his solution to the mind/body problem, as I have described it,
consists in his rejecting proposition (2).  And I believe from some of his
remarks (which I will consider below) that he actually thinks that quantum
mechanics does entail that (2) is false.  Thus, the position he is
endorsing is, apparently, pansychism, the view that the fundamental
constituents of things have mental properties.  I said in my commentary
that I did not think that pansychism had much going for it on either
classical or quantum mechanics.  I still think that's right.  The
properties evoked in both classical and quantum mechanics to explain
physical phenomena are not mental properties.  However, while I think that
our current physics gives us no reason to believe pansychism, I do not want
to say it is a crazy view.  It MAY be right.  No position on the mind/body
problem is a comfortable one, so it would be foolish to reject any
proposals out of hand.  However, I think we genuinely have no idea how it
could be true given our best picture of the way the world works.  I will
say below why I am unpersuaded by the reasons Stapp advances to think
otherwise.
 
Now I want to turn to the question whether that "the fundamental
constituents in classical mechanics are 'objects', [while] the fundamental
constituents in quantum mechanics are the 'wave function' (i.e., the state
vector) and the 'events' ...  undermines [my] discussion of the motivation
for proposition (2)."
 
First, it should be said that my use of 'fundamental constituents' was not
relativized to a theory.  So I was not talking about what things get
quantified over or are in the range of the variables in this or that
physical theory.  I was talking about whatever it is that we and other
macroscope objects are ultimately constituted out of, given that we have
parts.  If there are any objects at all, and things aren't infinitely
divisible, there will be some objects that count as the fundamental
constituents of all objects (there may of course be a variety of different
basic kinds of such fundamental constituents).  I am not sure whether or
not Stapp disagrees that there are such fundamental constituents but it is
important to note that that is what I meant by the term.  Proposition (2)
doesn't say anything about the content of either classical or quantum
mechanics, and is compatible with both as long as neither entails that there
aren't objects or that objects are infinitely divisible.
 
With this clarification in mind, what is it about quantum mechanics which is
supposed to undermine the motivation for proposition (2)?  It cannot be that
(2) is incompatible with the remark that quantum mechanics tells us about
the probabilities that certain events will occur.  That fact about quantum
mechanics would not show that (2) was false, or that electrons or protons
or quarks or neutrinos have mental properties, or that quantum mechanics in
fact traffics in mental predicates, and so attributes mental properties to
objects or events.  So far as I can see, the remark does not help us to see
why we should suppose that the fundamental constituents of objects have
mental properties.
 
Now, it may be that what Stapp has in mind is that quantum mechanics shows
that there are no objects at all, but only events (i.e., no bodies, no
brains, no tables or chairs, no rocks, no mountains, etc.).  The grounds
for this might be that what quantum mechanics is about is events.  I would
like some clarification about whether this is what Stapp has in mind.  It
is not clear to me it is.  However, if it is, I think we have not been
given enough reason to suppose that quantum mechanics requires us to reject
the view that there are objects in addition to events.  For one thing,
events require objects, since events are changes, an object's acquiring or
losing a property.  So, if there were no objects, there would be no
events.  (There are other accounts of events in the relevant literature,
e.g., Jaegwon Kim's but this would be no help to Stapp, since these
accounts treat events as properties, which require objects to be
instantiated.)
 
It is worth remarking, in any case, that even if one chose an event ontology
as one's basic ontology, the same problem would arise.  We simply need to
generalize the notion of a fundamental constituent so that it is indifferent
between objects and events, or any other thing one wants to take as
ontologically basic.
 
Here is one remark Stapp makes which suggests his reason for rejecting (2)
(there are others which I will come to):
 
> Quantum events have presumably been occurring ever since the big bang,
> and these events are presumably fundamentally the same as those complex
> events in human brains that are the conscious experiences that we know.
> Of course, human brains are endowed with a short-term memory that
> injects a special kind of informational content into these brain events
> that would not be present in primordial events, which, accordingly, would
> not have a comparable feel.
 
Notice, however, that in this motivation (essentially the endorsement of my
propositions (1), (3) and (4)), the appearance of the word "Quantum" is
superfluous.  A classical theorist could say exactly the same thing.  And
the same objections would be raised in each case, namely, no mental
predicates appear in our statements of our physical theories.  So if our
physical theories give a complete description of the universe a bit after
the big bang, there weren't any mental properties of any objects then.
 
So let us look elsewhere for a reason to think that quantum mechanics either
requires the rejection of (2) or undermines the motivation for it.  I think
there is something else which Stapp has in mind.  Here are some suggestive
remarks:
 
(a) "events can more naturally be experiential in character than objects."
 
(b) "events make 'selections' that are not determined by mechanical (i.e.,
localizable) aspects of quantum dynamics.  This makes them natural
candidates for thoughts.  For as William James concluded from a study of
'the particulars of the distribution of consciousness'... 'consciousness is
at all times primarily a selecting agency'".
 
(c) "the high-level informational content of the quantum state gives it the
same sort of infomrational content as a thought: it captures as a whole a
nonlocal information structure.  This characteristic of events reinforces
the idea that events are fundamentally different from anything that appears
in calssical mechanics, and are basically thoughtlike in character."
 
It appears from this that Stapp thinks that (a) events are by their very
nature the sorts of things that are thought-like, and (b) that classical
mechanics doesn't countenance events, while quantum mechanics does, so that
(c) quantum mechanics does entail a solution to the mind/body problem
because it entails pansychism, while classical mechanics does not.
 
Both of the premises of this argument are false.  First, events are not by
their very nature thought-like.  An avalanche in the Canadian Rockies is an
event.  Is it a thought?  Who is thinking it?  The mountain?  No, the
avalanche is not a thought, not even of the snow, although it is an event.
Likewise, a solar eclipse is an event.  Is it a thought?  Who is thinking
it?  The moon?  The Sun?  The two together?  Again, a solar eclispe,
althought an event, is not a thought.  Events are not by their very nature
thought-like.  They are, as I said, changes, and what kind of change they
are depends on what kind of property or properties they are changes with
respect to.  Second, as these examples show, events and talk about them has
been around as long as talk has been around, which is a lot longer than
quantum mechanics.  Events were not invented with quantum theory, and
classical mechanics of course was in the business of predicting events
(solar eclipses, e.g.).  So, both (a) and (b) above are false.
 
But it may be felt that while these remarks are correct, I am still missing
the point, for Stapp does emphasize the idea that events make selections,
and that consciousness functions to make selections, and that quantum
states have informational content, and that so do thoughts.  Don't these
suggest that there is something to the idea that quantum mechanics holds
the key to understanding the mental?
 
No.  Both 'selection' and 'information' are ambiguous.  If I select a
particular tomato from the pile at the grocery store, I perform an
intentional act, I choose one of the tomatos rather than any other.  In
this sense of the word, it refers to an event which must involve an
intentional agent.  We can also use the word (probably in its origin a
metaphor) when talking about events which when they occur determine that
one among a number of physically possible outcomes obtains.  This carries
no hint of the mental of course, for such selections could occur in worlds
which by hypothesis contain no thinking beings.  Likewise for
'information'.  The newspaper contains information in one sense of the
word, namely, it correctly represents certain things has having occurred
(it says that certain things have occurred).  The rings in the trunk of a
tree contain information in another sense: they don't say that the tree is
so many years old, but that the tree is so many years old can be inferred
from the number of rings in the trunk plus our account of what produces the
rings.  We should not think we can solve the mind/body problem with a pun.
(The remark about quantum states carrying non-local information content is
clearly beside the point once these two senses of the word 'information are
distinguised.)
 
 
Kirk Ludwig
kludwig@phil.ufl.edu
 
 
-----------------------------------------------------------------------
Kirk Ludwig                                       kludwig@phil.ufl.edu
Department of Philosophy                   voice: (904) 392-2031
University of Florida                        fax: (904) 392-5577
Gainesville, FL 32611-8545                  http: www.clas.ufl.edu\CLAS\
                                                  \Departments\Philosophy
----------------------------------------------------------------------

Home