SOME SUBATOMIC PARTICLES OF LOGIC
3.1. I CAN best begin this contribution to the articulation of speech acts with a consideration of the Fregian 'assertion sign', or, to speak more accurately, 'judgement stroke'. This correction itself warns us that there is not just one kind of sign that has to be examined, but several, and that an elucidation of this difficult subject has to begin with a careful distinction between them. Only then can we see which of these signs are necessities, or even possibilities, for logic--that is, what we are to say about Wittgenstein's complete dismissal of Frege's sign, in Tractatus 4.442 and subsequently, as 'logically quite meaningless'. I submit this discussion as a penance for having failed to make the necessary distinctions clear in my first book, in spite of being at least partially aware of them at the time (LM 2. 1.). I later made some of them in print, especially that between what I shall be calling signs of subscription and signs of mood (H 1970). In spite of this, the distinction is still often neglected; in particular, both Dummett ( 1973: 308) and Davidson ( 1984: 110) discussions would have been a great deal clearer if they had been more attentive to it. I should perhaps add that I have found Dummett's treatment of assertion rewarding, and agree with most of it.
Let us then look at some of the different things that are done by what I called in that book the 'neustic'. I am going to start with the easiest customer. I do not think that anybody could, on reflection, deny that a logical notation needs a sign of mood, if it is to handle sentences, or speech acts, or different kinds of things that are said, in different moods. This is evident, at any rate, if we need, in our logical notation, to have different expressions for sentences whose meaning is different. For it is clear that, for example, the Latin words 'i' and 'ibis' have different meanings, namely 'Go' and 'You will go'. I can see only two ways in which this conclusion could be avoided. One would be by confining logic to sentences in the indicative mood. This is sometimes____________________