Tuesday, December 2, 2014

Half an Hour: Constructivism and Eliminative Materialism

 We don't reason over perceptions or construct meaning, etc- there's no
mechanism to do that - rather, we gradually become better recognizer



The basic constructivist premise (and I mean constructivists generally,
not just those working in education) is that learning and discovery
proceeds by the creation or models or representations off reality, and
then carrying out operations in these representations. Usually these
representations are created using a symbol system - language,
mathematics, universal grammar, etc - composed of signs and rules for
manipulation. We create meaning or sense in these representations by
means of a semiotic system - a way of assigning meaning to individual
symbols, phrases, groups of symbols, or entire models, sometimes by
reference, sometimes by coherence, etc. (note that there are *many*
different variations on this common theme). These representations are
easy to find in the world - we can see instances of language and
mathematics, for example, in any book. But the theory argues that we
*also* have these systems in our minds - that we actually reason in our
heads by means of these representations, and hence that learning means
constructing these representations and assigning meaning to their
symbolic entities. Cf. for example the 'physical symbol system'
hypothesis. What I am arguing is that this position is wrong. That even
*if* we construct representations in our mind, there is no distinct
entity over and above the representation that does the constructing,
manipulation, or sense-making. Therefore, we do *not* learn in this way.



------------------------------------------------

Fred M Beshears



 It depends on which level of description works best for the problem at
hand. To describe the workings of a computer you could pick from the
following: logic gates, machine language, assembly language, a high
level programming language (e.g. Lisp), or the user interface.



Similarly with humans, you can pick from the following: an individual
neuron, a group of neurons (e.g. Kurzweil claims that it takes an
average of 100 neuron in the cerebral cortex to form a pattern
recognizer), or groups of pattern recognizers (Kurzweil claims there are
around 300 million pattern recognizers in the cerebral cortex), or
one's 1st person account of one's stream of consciousness (which for
many of us comes in the form of a sequence of words).



Of course, animal consciousness is probably very different from human.
And, with computers, we know how to map from one level of description to
another. But, with biologically evolved brains, we still have a long
way to go before we've completely reverse engineered the brain.



As for educators, I don't know if there is one "correct" level of
description. Some may prefer folk psychology, others neuroscience.



----------------------------------------------------

Stephen Downes



Not all descriptions are simply 'levels of description'. Some are simply
wrong and should be eliminated from the discourse. For example,
discussion of 'phlogiston' was not just some level of description, it
was just wrong. If you say that your computer has a soul, it's not just a
level of description, it's wrong. And when educators use 'folk levels
of description', they should be aware that their discourse is no more
reliable than phrenology or reading the Tarot. I don't think that being
an educator is a license to use whatever terminonology and ontology they
please.



------------------------------------------------------

Fred M Beshears



There may be some eliminative materialists out there who have jumped the
gun and are now starting to claim the folk psychology has been
successfully eliminated by neuroscience! Eliminative materialism may
someday turn out to be right, but it would be very wrong for them to
claim that they have proved their case as of today - especially if they
try to do so by simply making selective references to physics.



Some folk theories of science - such as phlogiston - have been
eliminated and have been consigned to the history books. And, some
eliminative materialists working in the fields of cognitive psychology
and neuroscience selectively refer to these examples to bolster their
case. In the case of cognition, the eliminative materialist believes
that since this has happened in some cases in physics it will someday
happen in cognitive psychology, too. In other words, the eliminative
materialist believes that neuroscience will someday eliminate folk
psychology; it will not simply match up with folk psychology categories.



But, there are at least two other materialist schools of thought that we
should also consider: reductive materialism and functionalism.



Reductive materialists (aka identity theorists) believe that someday
folk psychology will be reduced to neuroscience. In other words, they
believe that each mental state of folk psychology will be found to be in
a 1-to-1 relationship with physical states of the brain. They, too, try
to support their theory by making selective references to physics. So,
the identity theorist will say that in the case of sound we know that as
a train compresses air it creates sound waves, and that high pitched
sounds are the property of having a high frequency of oscillating waves
in air. We later learned that light was an electromagnetic wave and that
the color of an object is related to the reflective efficiencies of the
object, much like a musical cord. But the notes in the case of light
are electromagnetic waves. So some reductive materialists in the field
of cognitive psychology (like some eliminative materialists) use
selective references to physics to bolster their case - i.e. that
someday there will be a intertheoretic reduction between folk psychology
and neuroscience.



Functionalism is yet another form of materialism. According to Paul
Churchland, the functionalist believes the "essential or defining
feature of any type of mental state is the set of causal relationships
it bears to (1) environmental effects on the body, (2) other types of
mental states, and (3) bodily behavior." (p. 63 of Matter and
Consciousness 2013) Unlike the behaviorist who wants to define mental
states solely in terms of inputs from the environment and behavioral
outputs, the functionalist believes that mental states involve an
ineliminable reference to a wide variety of other mental states, which
makes impossible the behaviorist game plan. Functionalists are at odds
with reductive materialists, too. So, the functionalist would argue that
a computer or an alien from another planet could have the same metal
states that humans do (e.g. pain, fear, hope) even though they implement
these mental states in a different physical substrate. According to
Paul Churchland: "This provides a rational for a great deal of work in
cognitive psychology and artificial intelligence, where researchers
postulate a system of abstract functional states and then test the
postulated system, often by way of its computer simulation, against
human behavior in similar circumstances."



But there are arguments against functionalism, too. For example, many
functionalist AI researchers try to model thought as "an internal dance
of sentence-like states, a dance that respects the various inferential
relations holding among [propositions]" (p. 80 in Mind and Matter) But
although humans do have a command of language, and most 1st person
accounts of human thought do involve language, there are obviously other
creatures with brains that do not.



Churchland provides a very balanced presentation of these three
perspectives. And, he doesn't try to make the case that eliminative
materialism has triumphed over the other two perspectives by simply
making selective reference to the cases in physics that support his view
(which is a moderate form of eliminative materialism).



----------------------------------------------------------------------



Stephan Downes



Hiya Fred, I am of course familiar with identity theory and
functionalism (you can see references in my latest presentation) and I
am of course familiar with Paul Churchland. Your overview is quite
correct as a broad account of some major recent theories in the
philosophy of mind.



Now of course I am not going to claim to have defended elimininative
materialism in one or two paragraphs (or even in my recent talk, in
which I discuss both identity theory and various forms of functionalism,
as well as Thomas Nagel and the cognitivist position of people like
Fodor and Pylyshyn).



My response to you was to indicate that folk psychology is not
automatically correct, and that something akin to Dennett's 'intentional
stance' might not be reasonable if in fact the position I argue for is
correct. Indeed, I think that folk psychology is deeply flawed (cf
Steven Stich 'From Folk Psychology to Cognitive Science'). In
particular, if the claims made by folk psychology (and for that matter
constructivism) are literally true, then we descend into nonsense and
contradiction.



But what I would also like to be clear about is that in this case as in
all cases I am explaining my line of reasoning. This is where my
thoughts have led me. I'm pretty sure I'm right, but I don't expect
anyone to be swayed by my arguments (this makes my quite unlike most
theorists in education). I develop learning systems based on my
theories, and if they work, that is my argument.







Half an Hour: Constructivism and Eliminative Materialism: A few months ago Fred M Beshears and I discussed Constructivism and Materialism. He compiled the conversation and ...

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