Re: The Other-Minds Problem

From: Harnad, Stevan (
Date: Tue Feb 25 1997 - 15:12:53 GMT

I'll reply to Phin, but let me warn those who do not have a stomach or
mind for philosophy to skip this thread!

> From: Head, Phineas <>
> The... "Other Minds Problem", the gist of
> which runs thus: I can (probably) prove (at least to myself) that I
> have a mind, (what ever that is) but YOU can never prove to me that YOU
> do. And vice-versa.

The Other-Minds Problem is not something to worry about, but it is a
definite limitation on what we can know for sure: Descartes, on the
basis of his "Method of Doubt" (trying to think of everything he knew
and seeing whether it was certain or open to doubt), found that there
were only two things that he could be absolutely certain about:

(1) The first of Descartes' certainties were the truths of mathematics
(and logic), because they were true on pain of contradiction (supposing
them to be false leads to a contradiction, as in a "reductio ad absurdum"

Outside formal mathematics and logic, however, there is no proof. So
Descartes found he could doubt all the truths of science; there was no
certainty there. But that doesn't mean that he thought science was
false! It only means that the truths of science are not provably true,
hence they are not certain. (In practice, this is no problem: For our
purposes, "overwhelmingly likely" is as good as "certain on pain of
contradiction." "Not certain" certainly doesn't mean "not true"!)

(2) Descartes' second and most famous certainty was the one he
formulated as "Cogito Ergo Sum" ("I think, therefore I exist"), but
that formulation has since been found to be ambiguous. A better way of
stating it would be "I am doubting, therefore I cannot doubt that there
is doubting going on," but that's a bit wordy and awkward. This version
is much simpler: "I am experiencing, hence there is experiencing going

In other words, Descartes saw he could not doubt that he had a mind
(or better, that he was a mind, where mind just means having/being
conscious experiences, feelings). The Cogito was a certainty.

Not so the minds of others, or even the existence of the outside world:
Again, as with scientific truth, the existence of the external world and
of the minds of others is overwhelmingly likely, but it is not certain.

For centuries, therefore, the other-minds problem was merely an
intellectual curiosity, and certainly had no bearing on people's lives.
It DID have a bearing on other creatures' lives, however, for Descartes
suggested, for some reason, that unlike people, who have souls
(= minds), animals do not; they are merely mechanical robots.

The latter is of course almost as certainly false as that people other
than myself have minds, so Descartes may have been responsible for some
of the mistreatment our species has visited on other species, but
probably his views were only used as a rationalisation, because people
were bent on exploiting and abusing other species anyway.

Let's leave this unfortunate aspect of Descartes' legacy aside. Some
people also think the Mind/Body Problem was Descartes' invention and
hence "dualist" thinking was his fault! Actually mind/matter dualism had already
been around for millenia before Descartes in the form of the belief in
the immaterial soul. It is something everyone knows, if they think about
it, that there is something special and different about having a mind:
One can be as sure as it is possible to be that one has a mind, but one
can't be quite that sure about anyone else! Never mind, overwhelming
likelihood is just about as good as certainty.

> It seems to me that this argument, while not DISprovable, fails because
> none of us, if we are absolutely honest with ourselves, believes it.

Phin, you've got it backwards: My having a mind is certain; to think
about it is already to confirm it, by doing the thinking. The
uncertainty about minds other than my own, like the uncertainty about
the reality of the world and the truths of science is merely that:
the lack of certainty. They are nevertheless overwhelmingly likely.
So it's not a question of the disprovability of doubts about there being
other minds; it is merely the nonprovability of it. Big deal!
F = ma and e = mc squared are not provable either.

The possibility of doubt (often called "skepticism) does not entail
disbelief or even agnosticism. We can be as sure that others have minds
as that tomorrow the sun will rise, streptomycin will cure strep throat
and the earth orbits the sun. We just cannot be AS sure of it as we are
of 2 + 2 = 4 or that we have/are minds/experiencing.

There IS an emerging area now in which the other-minds problem becomes a
practical one: How can we know whether robots have minds? This is where
Turing testing comes in.

> In
> short it becomes a sort of convenient 'arguing tool' with which to play
> cognition's Devil's advocate. We cannot possibly believe it because to
> do so would be to think in a similar way to a psychopath, s/he who has
> no regard for the feelings of others, since no mind = no feelings. Mind
> you, for all that, I still can't PROVE anything else does have a mind,
> I just assume they do so I don't hurt their 'feelings'. And, I suppose,
> their mind.

I hope that after the kid-sib explanation above you will now have this a
bit better sorted out: Uncertain does not mean untrue. (It's a pity
that Descartes only gave people and not animals the benefit of the

> 2. Next, is the rather worrying state of affairs that to date, with
> the exception of Professor Harnad, no one has suggested that anything
> other than humans possess a mind.

Surely there are billions of people who know that animals have minds.
How they justify treating them as chattle anyway should surprise no one:
we do the same with other human beings too. (Pick your favorite example:
ethnic cleansing in Bosnia and Rwanda/Burundi will do.)

> As an extension of this, is 'mind' = 'life'? Plants are alive but don't
> think (I think.....?) so where does that put them since life wants to
> live and, I suppose, mind wants to think?

I hope plants don't have feelings or there is nothing left for me
(or you) to eat! Anyway, it's a safe bet that having feelings is closely
tied to having a nervous system, which plants (and the living creatures
in our intestines, and the individual cells of our bodies) lack.

> 3. Thirdly, is 'thinking' in the sense of 'working things through in
> one's head', the 'voice inside my head', separate in origin from
> speaking (and actual verbalisation)?

Surely it is, as Kohler's famous observations on insight in chimps
show. But thinking need not be verbal.

> The reason I ask is that I know you (Prof. Harnad) are Hungarian, so do
> you 'think' in your first language and translate, or in which ever is
> appropriate to the circumstances?

We have introspective evidence that we "think" in images and in words.
But since introspection can't tell us HOW we think, we need to await the
successful model that explains thinking. It may or may not turn out that
that ultimate, correct explanation of the mind will use images and
words; it may instead leave images and words (like free-will) as byproducts
and side-effects of the real mechanism doing the thinking: a kind of
cognitive sop to keep us satisfied that we're really the ones doing the
hard work.

Introspection certainly cannot answer these questions.

> 4. Finally, are religion and cognition TOTALLY
> incompatible bedfellows?

Uncertainty cuts both ways: What is not provably true is also not
provably false. So one is free to believe in anything but a square
circle and the nonexistence of one's own mind. I do think, though,
that the mind/matter problem is also the source of belief in the
immaterial soul.

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