Re: Descartes and the Mind

From: Harnad, Stevan (
Date: Thu Oct 19 1995 - 22:38:47 BST

> From: "Matsers, Kate" <>
> Date: Thu, 19 Oct 1995 12:36:18 GMT
> If we can only be CERTAIN of something given that it is based upon the
> condition that we are NOT UNCERTAIN surely the ability to be certain
> and thus the ability to doubt can only be conceptualised within the
> world in which they were constructed. DOUBT and CERTAINTY have been
> constructed as concepts by human thought. But can these concepts be
> DOUBTLESS and CERTAIN if we are capable of doubting our existence?

You're jumping way ahead of the cogito here! Whether concepts are
constructed or discovered is a question to ask later in the day. The
issue with Descartes is that it makes no sense to doubt that experiences
are going on ("in your mind," whatever that means), because doubting
itself is an experience. So that's something you can be sure of.

The tight relation (identity, actually), between certainty and
not-uncertainty is also guaranteed on pain of contradiction.
Distinguish, though, between subjective certainty (when you FEEL sure
something is true) and objective certainty (when something is
necessarily true). The truths of mathematics are of the latter kind,
whether an individual happens to "get" it or not.

> I began writing this as an argument against Cartesian philosophy and
> I thought my way into agreeing with him. If we could doubt our own
> existence we would be making CERTAINTY self-contradictory which is,
> to quote Stevan "a nonsense".

Not quite. And I didn't say anything about our own existence (even
though that's the traditional way of putting the cogito, and the way
Descartes himself put it). I just said it makes no sense to doubt that
an experience is going on (when it's going on), because doubting is itself
an experience. "Cogito ergo sum" would then be saying: "I can doubt
a lot of things (everything but mathemtatics), but I can't doubt that
doubting is going on."

sh> These are the two things we can be
sh> certain about: the truths of mathematics and the reality of
sh> experience. All else is open to doubt." (s. Harnad, 1995)
> I also see that it is important for us to interact with each other
> as therefore we can juxtapose the theoretical, academic psychology
> with the subjective, social and personal psychology.

Fine, but again you're getting ahead of the game! "Each other" (like the
rest of the outside world) IS open to doubt. You may just be interacting
with yourself, when you think you're interacting with others!

> "Psychology is such a new science that you are still plonking things
> together and seeing what happens as Alchemists did when they wanted
> to sort out the Periodic table."
> "Nice idea but psychologists never discover any facts because they
> can't quantify anything realisably".

This is a bit premature too, and not exactly supported by evidence or
argument as stated here! On the face of it, psychologists quantify a
lot. (How much we learn from it is another matter.)

> If philosophers are still uncertain of whether anything exists
> except our seeming to experience things, how the **** are we
> supposed to tackle the structure and function of, and processes
> involved in thinking and seeming to experience? Its a bit like
> trying to work out how water comes to the boil when you haven't quite
> accepted that the kettle exists - let alone that it has internal
> functions and that heat can be transferred!
> Am I just a wimp or is psychology possibly one of the most
> impossible subjects as nothing is certain?

You're going to fast; we're still in the 17th century now, and
psychologists are not doing anything yet! This is still just
philosophical foundations. We went back to Descartes and the cogito to
start fleshing out what is special about the mind, with a view
(eventually) to asking what would be a science of thought (cognition).

In point of fact, once you've convinced yourself that you can be sure of
the truths of mathematics and the reality of experience (but nothing
else), you can start putting things together again, and we will!

Chrs, S

This archive was generated by hypermail 2b30 : Tue Feb 13 2001 - 16:23:55 GMT