 In the case of sensations, the parallel temptation is to suppose that they are self-intimating. Itching, for example, seems like this: one just feels what it is directly; if one then gives the sensation a name, the rules for that name’s subsequent use are already determined by the sensation itself. Wittgenstein tries to show that this impression is illusory, that even itching derives its identity only from a sharable practice of expression, reaction and use of language. If itching were a metaphysical absolute, forcing its identity upon me in the way described, then the possibility of such a shared practice would be irrelevant to the concept of itching: the nature of itching would be revealed to me in a single mental act of naming it (the kind of mental act which Russell called ‘acquaintance’); all subsequent facts concerning the use of the name would be irrelevant to how that name was meant; and the name could be private. The private language argument is intended to show that such subsequent facts could not be irrelevant, that no names could be private, and that the notion of having the true identity of a sensation revealed in a single act of acquaintance is a confusion.