Wittgenstein and the problem of other minds
There will be no conclusion here, just some aimless wandering.

I can know what someone else is thinking, not what I am thinking. It is correct to say 'I know what you are thinking', and wrong to say 'I know what I am thinking'. "A whole cloud of philosophy condensed into a dropdropdropdropdrop of grammar."

Can we know if there are Other Minds aside from our own?

Perhaps there isn't really a 'problem' to begin with. Perhaps the problem is simply a misunderstanding of the subtleties of language; if we look at it from a grammatical point of view, the problem dissolves, leaving nothing but a chalky residue on the roof of our mouth. It is quite possible that the very way that we formulate this apparent problem makes the problem seem senseless, or ridiculous.

Or there may be the appearance of antagonism between our knowledge of ourselves and our knowledge of others; this appearance may turn out to be illusory (baseless). It is possible that the apparent problem of knowing whether or not other minds exist is not a problem about the existence of others (an ontological problem) but a problem about the grammar of the word 'know'. Perhaps it is a fundamentally linguistic problem.

Wittgenstein approaches this problem in a number of ways. Rather than 'solve' the problem or even search for a solution, he points out the arbitrary (dogmatic?) assumptions that the very formulation of the problem is based upon. He attacks the question rather than formulating an answer.

Throughout the first section of his Philosophical Investigations Wittgenstein focuses his attention on whether or not we can 'know' if someone else is in pain. His discussion of pain provides some good examples for our current subject. For instance, in section 246 he begins his attack on (or description of) our usage of the word 'know' in relation to the pain of others and our own pain:

In what sense are my sensations private?-- Well, only I can know whether I am really in pain; another person can only surmise it. --In one way this is wrong, and in another, nonsense. If we are using the word "to know" as it is normally used (and how else are we to use it?), then other people very often know when I am in pain.-- Yes, but all the same not with the certainty with which I know it myself! --It can't be said of me at all (except perhaps as a joke) that I know I am in pain. What is it supposed to mean - except perhaps that I am in pain? ... The truth is: it makes sense to say about other people that they doubt whether I am in pain; but not to say it about myself. (Section 246)
In this case the word 'know' is not an expression of certainty (as it is taken to be in the formulation of the problem we are dealing with), because we can not really be said to 'know' that we ourselves are in pain, though we are obviously certain that we are in pain. Within the ordinary use of the word 'know', others can be said to know that we are experiencing pain, it is simply that this use of the word 'know' does not preclude the possibility of all doubt. Wittgenstein aptly notes later on that the reader should "just try--in a real case- to doubt someone else's fear or pain" (Section 303). It is both ridiculous and redundant to say that I know I am in pain. But, we can say we 'know' someone else is in pain (with less certainty than when we ourselves are in pain) because we do not doubt it. That is, there is the possibility of doubt when someone else is in pain, but we still 'know' that they are in pain as long as we do not, in fact, doubt it. For our own pain, however, the very possibility of doubt (and of 'knowing' in the sense given above) becomes an absurdity- something senseless.

In section 247 he describes another use of the word 'know':
"Only you can know if you had that intention." One might tell someone this when one was explaining the meaning of the word "intention" to him. For then it means: that is how we use it. (And here "know" means that the expression of uncertainty is senseless) (Section 247).
Which is to say that in this case 'know' does not mean that there is the possibility of doubt, and that doubt is not being expressed (as in 246) but that the very possibility of doubt is ridiculous and senseless.
is he just making fun of us? What he may be getting at here is that a word can have two fundamentally incompatible meanings, yet, both meanings can still be effectively used. It is the surroundings of the word (its context) that determine how it can or cannot be used; but the borders of a context are often (usually!) hazy and indistinct, and not particularly easy to fit into a neat compact theory...((like trying to make a house out of air.)) Thus, to propose that we cannot 'know' other minds has become a confusing proclamation indeed if we consider just two possible uses of the word 'know'. Wittgenstein has begun to sow some seeds of discomfort within the original formulation of the problem by calling into question whether or not the word 'know' is (or can be) rigorously determined . Whether there is a problem to be dealt with here at all begins to be questioned. A flaw in the grammar may in fact be the problem... Beyond the grammatical attack on the problem, Wittgenstein also looks at the presupposed supremacy of subjective knowledge as compared to our knowledge of the 'exterior' world (and thus other minds). This supremacy is a legacy of Cartesian rationalism and taints everything it touches... as far as I'm concerned. Basically, the Cartesian assumption is that we are (a priori) more certain about our own thoughts than we are about the world around us (including our body if you want to be hardcore about it). Wittgenstein converses with his imaginary interlocutor:

Let us assume there was a man who always guessed right what I was saying to myself in my thoughts... But what is the criterion for his guessing right? Well, I am a truthful person and I confess that he has guessed right. --But might I not be mistaken, can my memory not deceive me? And might it not always do so when-- without lying-- I express what I have thought within myself? --But now it does appear that 'what went on within me' is not the point at all... (Page 222)

Here Wittgenstein is saying that our own memories (memories of our private experiences included...) are subject to the same fallibility as our experiences of the exterior world. If there were a private language, it would not be verifiable or justifiable because to verify one has to appeal to something independant. Hence, when the 'mind reader' guesses what you just thought, your memory of that thought cannot be incorrect because the very notion of correct/incorrect is misplaced in this context. Just as we cannot say that we 'know' we are in pain (when we are in fact in pain) without it being absurd, we cannot say that we remeber something 'correctly'. This is precisely because whatever we believe we are remembering just is what we are remembering! We are remembering whatever it is that we are remembering at the time. There is no criteria for verifying whether or not we are remembering something correctly, nor could there be because the idea of verification is senseless here (though not elsewhere...).

This all ties in very nicely with Wittgenstein's arguments against private language. Because the criteria for verification are public (not private; we can't verify our own memory...) the proposition of a solipsistic theory within a necessarily public language becomes absurd. If we wish to compare verification to following a rule (a fairly easy comparison, as verification is a sort of rule-following) we can look at section 202 of the Investigations. Here he states that "'obeying a rule' is a practice. And to think one is obeying a rule is not to obey a rule. Hence it is not possible to obey a rule 'privately': otherwise thinking one was obeying a rule would be the same thing as obeying it" (section 202). Which is to say, our private experiences (thinking one is obeying a rule) cannot be made subject to any criteria of verification, because we cannot formulate the a language with which to talk about them. It cannot be incorrect to say 'I remember it this way...' because you do remember it that way, and there is no way to check it against something. Memory cannot be held up against a table and compared other than to itself. (The comparison of one memory to another is not verification either. Wittgenstein reminds us of someone who bought "several copies of the morning paper to assure himself that what it said was true" (Section 265)).

The language we use to propose the problem of other minds contains in it the implicit assumption that there exist other minds with which we communicate. Thus, asking whether or not there are other minds becomes utterly senseless.

An analogy:  "Flying is impossible"
Said by someone on a plane in midair.
(Though the plane may be one without windows, that you have never been outside of).

Essentially, the problem (because it must necessarily be formulated within the confines of a public language) always already presupposes its own answer; that other minds do exist.

The fundamental difficulty of escaping language...

((it's like smashing your head against a wall))

Wittgenstein attacks the idea of using common language to describe apparently private sensations in several other pasages. In 261 (following the diary example of 258 where a person writes "S" everytime they have a particular sensation) he asks:

What reason do we have for calling "S" the sign for a sensation For "sensation" is a word of our common langauge, not one intelligible to me alone. So the use of this word stands in need of a justification which everybody understands. --And it would not help either to say that it need not be a sensation; that when he writes "S", he has something-- and that is all that can be said. "Has" and "something" also belong to our common language. --So in the end when one is doing philosophy one gets to the point where one would just like to emit an inarticulate sound. --but such a sound is an expression only as it occurs in a particular language game, which should now be described (Section 261).

That part about inarticulate sounds always makes me laugh out loud

Even to say "I have something" is part of a common language! Soemething as complex as asking whether other minds exist is utterly ridiculous (in the same sense that doubting one's own pain is ridiculous).

Wittgenstein's unique treatment the 'great metaphysical problems' of Western thought as grammatical errors avoids the necessity of solving those problems by dissolving them in their own presuppositions. He doesn't so much solve the problem of other minds as much as he dismisses the fact that it can be asked. He says "the philosophical remarks in this book [Philsophical Investigations] are, as it were, a number of sketches of landscapes which were made in the course of these long and involved journeyings" (ix) That is to say: through the various microcosms of argumentation we have discussed above (private language, rule following, pain, etc.) we begin to see a certain terrain (not necessarily a systematic one) elucidated.

***Indefinite Adjournment***

All references are to... Ludwig Wittgenstein, Philosophical Investigations translated by G.E.M. Anscombe (the strange edition I have has no publishing information...)