dispensable in logic, only because language itself prevents every logical
mistake.--What makes logic a priori is the impossibility of illogical
thought.


5.4732 We cannot give a sign the wrong sense.


5,47321 Occam's maxim is, of course, not an arbitrary rule, nor one that is
justified by its success in practice: its point is that unnecessary units
in a sign-language mean nothing. Signs that serve one purpose are logically
equivalent, and signs that serve none are logically meaningless.


5.4733 Frege says that any legitimately constructed proposition must have a
sense. And I say that any possible proposition is legitimately constructed,
and, if it has no sense, that can only be because we have failed to give a
meaning to some of its constituents. (Even if we think that we have done
so.) Thus the reason why 'Socrates is identical' says nothing is that we
have not given any adjectival meaning to the word 'identical'. For when it
appears as a sign for identity, it symbolizes in an entirely different way--
the signifying relation is a different one--therefore the symbols also are
entirely different in the two cases: the two symbols have only the sign in
common, and that is an accident.


5.474 The number of fundamental operations that are necessary depends
solely on our notation.