Wittgenstein offers a remarkable solution to the problem of the truth-values of statements ascribing propositional attitudes:
5.54 In the general propositional form, propositions occur in a proposition only as bases of the truth-operations.
5.541 At first sight it appears as if there were also a different way in which one proposition could occur in another. Especially in certain propositional forms of psychology, like “A thinks, that p is the case”, or “A thinks p”, etc. Here it appears superficially as if the proposition p stood to the object A in a kind of relation. (And in modern epistemology (Russell, Moore, etc.) those propositions have been conceived in this way.)
5.542 But it is clear that “A believes that p”, “A thinks p”, “A says p”, are of the form “‘p’ says p”: and here we have no co-ordination of a fact and an object, but a co-ordination of facts by means of a co-ordination of their objects.
How is a proposition like “A believes that p” applied?
I say “Dave believes that we’re all talking nonsense.” I might have just heard Dave say “You’re all talking nonsense.” Or I might have heard Dave construct a clever parody of what we were just saying. Or I might just be watching Dave squirm in his seat while I’m off in some aside about scientific realism and, remembering that Dave has some Carnapian and nominalist tendencies, I can see the symbol (which is p – “You’re all talking nonsense”) in the sign (his squirming).
There isn’t any device which allows us to read off beliefs from neurological states that I know of, and it’s not clear that such a thing could be done. But if there were that would be fine too. Likewise a telepathic sense, etc. Any method of belief ascription ought to do.
If I say “My dog Winnie is on the Tunisian rug” and you’re in the room with me you can look for the rug and see if there’s something doggish on it, or just look for Winnie if you know her. If we’re talking on the phone and I’m saying the same thing you can’t do that, but if you understand what I’m saying you’d know that that was the sort of thing you’d do to apply the statement to reality.
It’s exactly the same thing with “Dave believes that we’re all talking nonsense.” In essence, the things Dave says and does are signs, in which we can see, hear, or think various propositions.
3.12 The sign through which we express the thought I call the propositional sign. And the proposition is the propositional sign in its projective relation to the world.
‘p’ says p has given many commentators pause because they forget that for Wittgenstein “the propositional sign is a fact” (3.14) – “the propositional sign is articulate” (3.141). Consider also in this connection 4.022: “The proposition shows how things stand, if it is true. And it says, that they do so stand.” “‘p’ says p” is nonsense in exactly the same way as 4.022 is; the sign, ‘p’, says nothing by itself, qua object, these syntactic tokens or that set of behaviors; it is only the sign ‘p’ as understood, in its projective relation to the world, that says anything at all; but that just is the proposition.
So when we say “Dave believes that we are all talking nonsense,” we are saying that Dave himself is in effect a sign symbolizing “we are all talking nonsense,” which could be expressed in behavior or words or even privately by Dave to himself through a certain quiet aggravated shrugging of the shoulders. And Dave’s belief is that that Ein Zeichen sind wir, deutungslos, just as Hölderlin had it: we are talking, but our words lack meaning.
“A coordination of facts by means of a coordination of their objects”: let’s switch to Winnie on the rug for a moment for convenience. The words I type, my thought of her as I look on, Kira’s gesture with her head after Miriam asks “where’s the dog?” and so on – and, if p is true, Winnie herself sitting on that Tunisian rug – all share the same structure, which is shown by thought and reality alike. (The gramophone record, the musical thought, the score, the waves of sound – 4.014.)
So now we are ready to understand 5.5421:
“This shows that there is no such thing as the soul – the subject, etc. – as it is conceived in contemporary superficial psychology. A composite soul would not be a soul any longer.”
Although there are interesting points of contact between Wittgenstein and Hume, I don’t think this is one of them, as some commentators have suggested. We don’t need ‘the soul’ because we don’t need to posit any sort of subject to evaluate propositions of the form “A believes that p.” To believe that p is just to be a sign/symbol for p yourself – and this definition holds in the first person (as when you say or think p) just as it does in the third. p can be asserted in your own words or thoughts or behavior or someone else’s words or thoughts or behavior – and it is the same p in all of them.
So the problem of the ‘composite soul’ here is not that some weird hybrid entity including person-objects and proposition-facts is incoherent – it’s that the things that were supposed to be possessed by the souls/minds/subjects in question aren’t possessed by them at all. We don’t need the hypothesis in the first place. Rather we – whatever we are, plain old persons or souls in some other sense – just instantiate them, serve as signs for them, at various times in various ways. If “Dave believes that p” just means that Dave is being a sign symbolizing p just as someone else’s words or thoughts or behavior might, then you can’t call that belief any sort of possession of a mind our soul, because it would be the same belief in my mind and in yours and in the minds of anyone else who thought it. It’s a zusammengesetzte, an agglomeration of disparate things that doesn’t at all track the individuals who were supposed to be the possessors of this sort of soul in the first place.
Plausible as an interpretation?
Is the view defensible more generally? I suspect it might be the only possible one if the Tractatus’ discussion of sense and the relationship of propositions to reality holds up, so perhaps that is really the place that one would want to dig in, but we can raise the question independently here too.
At the beginning of the post I said that Wittgenstein was here dealing with “the propositional attitudes”, but we have only talked about belief. What about “Travis fears the tiger?” Well, if we see Travis running from a tiger, his fear-behavior works just fine to symbolize “Travis believes that there is a tiger chasing him” too.