This remark provides a key to the question, to what extent solipsism is a truth.
In fact what solipsism means, is quite correct, only it cannot be said, but it shows itself.
That the world is my world, shows itself in the fact that the lists of the language (the language which only I understand) mean the limits of my world.Elizabeth Anscombe, in her book An Introduction to Wittgenstein’s Tractatus, relates Wittgenstein’s solipsism to his view of logic. Here’s an excerpt from Chapter 13, "Mysticism and Solipsism” :
In the Tractatus Wittgenstein speaks of 'my language’ (5.6) and explains this as meaning 'the only language that I understand' (5.62). Its limits 'stand for the limits of my world’. I cannot postulate a language for talking about the relation of language, the world, and the philosophical I, in which my world (the world given by the limits of my language) would be one particular thing to talk about. I can only say how things are in the world corresponding to my language. But this manifests 'the 'all-comprehending world-mirroring logic’.
That is why, having said at 5.6 'The limits of my language mean the limits of my world’, Wittgenstein gives as the first comment on this pronouncement a number of remarks on logic: 'Logic fills the world: the limits of the world are also its limits' (5.61). The argument is: 'The limits of my language mean the limits of my world; but all languages have one and the same logic, and its limits are those of the world; therefore the limits of my world and of the world are one and the same; therefore the world is my world.'
But the ‘I’ of this way of talking is not something that can be found as a mind or soul, a subject of consciousness, one among others; there is no such thing to be 'found' as the subject of consciousness in this sense. All that can be found is what consciousness is of, the contents of consciousness: 'I am my world' and The world and life are one'. Hence this T, whose language has the special position, is unique; the world described by this language is just the real world: Thoroughly thought out, solipsism coincides with pure realism' (5.64).
It is not possible to understand this passage unless one has a good deal of sympathy with solipsism. We should remember that Wittgenstein had been much impressed by Schopenhauer as a boy; many traces of this sympathy are to be found in the Tractatus. Probably no one who reads the opening of The World as Will and Idea: "The world is my idea', without any responsiveness, will be able to enter into Wittgenstein's thought here.According to Anscombe, it's difficult to get rid of one’s conception of solipsism once one has developed it. One may want to get rid of such a conception because one may feel that it makes the ‘I’ too godlike, but it's not easy to free oneself from solipsist thoughts. She notes that in Wittgenstein’s version, “It is clear that the ‘I’ of solipsism is not used to refer to anything, body or soul; for in respect of these it is plain that all men are alike. The ‘I’ refers to the centre of life, or the point from which everything is seen.”