Abstrakt
This paper aims to shed light on the broader significance of Frege's logicism (and hence the phenomenon of modern logic) against the background of discussing and comparing Wittgenstein's 'showing/saying'-distinction with Brandom's idiom of logic as the enterprise of making the implicit rules of our linguistic practices (something we do) explicit (by something we say). The main thesis of this paper is that the problem of Frege's logicism lies deeper than in its inconsistency (which has since turned out to be reparable, as the neologicists have shown): it lies in the basic idea that in arithmetic (and prospectively in language in general) one can, and should, express everything that is implicitly presupposed so that nothing is left unsaid.
This, in fact, is the target of Wittgenstein's critique. Rather than the Tractatus, with its claim that logicism attempts to say something that can only be shown (e.g. what 'object', 'function' or 'number' are), it is the Philosophical Investigations, with its argument by regress against the thesis that every rule which one can follow must be of an explicit nature, that is of real significance here.