Re: Pylyshyn: Against Imagery

From: Harnad, Stevan (
Date: Wed Jan 17 1996 - 20:00:56 GMT

> From: "Parker, Chris" <>
> Date: Tue, 28 Nov 1995 08:18:13 +0000 (GMT)
> Just an extra bit about Pylyshyn: he says that for computer
> modelling of cognition it must match cognition in detail.
> I assume that a mechanical model of a human arm that included
> a flexible tube with a sucker on the end would therefore
> fail according to Pylyshyn, even if the condition-action pair
> (in this case the goal/stimulus-behaviour pair) turned out to
> be the same. The difficulty is what correspondence can made to
> a hidden system? Through cognitive processes or physiological
> bits of the brain?

You are talking about matching performance; Pylyshyn is talking about
matching "cognition." Since for Pylyshyn cognition = computation, that
means that you have to match at the "functional" level of the software.
That means internal states, but not necessarily physiology, since the
hardware details are irrelevant. The same programme could be run on
radically different software. It is at the programme level that the
match must be exact. This is also called "strong equivalence." Weak
equivalence is mere inout/output performance equivalence.

This archive was generated by hypermail 2b30 : Tue Feb 13 2001 - 16:23:57 GMT