LOGIC AND THE SYNTHETIC A PRIORI (1949)

The distinguished American logician, C. H. Langford, recently published a paper (Langford 1949), as brief and alarming as what the title, “A Proof that Synthetic a priori Propositions Exist,” claims for it. Although this publication has, to my knowledge, had no noticeable repercussions in the literature of analytic philosophy, it deserves credit for reopening (for open minds, that is) an issue which according to the logical positivists has been decided once and for all. One of the merits of logical positivism which I would be the last one to deny is to have revealed a typical character of philosophical disagreements, viz., the fact that many (or most, or all?) philosophical controversies are rooted in differences of verbal usage. I am fairly sure that Langford’s paper constitutes, indeed, further confirmation of this positivistic thesis, for a positivist is not likely to deny the cogency of Langford’s proof of the existence of synthetic a priori propositions in Langford’s sense of “synthetic a priori.” He would rather criticize Langford for having suggested by his terminology an accomplishment which he cannot really claim. I hope, therefore, to shed some light on this issue by scrutinizing the Kantian concepts involved in terms of modern logic. Indeed, it seems to me just as futile to discuss the nature of logic without a clear understanding of the distinctions which Kant strove (though rather unsuccessfully) to clarify as to discuss those distinctions without regard (be it ignorance or oblivion) to modern logic.