Abstract

In his essay “Logical Empiricism”, in the anthologyTwentieth Century Philosophy, Professor Feigl writes: “All forms of empiricism agree in repudiating the existence of synthetic a priori knowledge.”2Schlick makes the same point even more forcibly: “The empiricism which I represent believes itself to be clear on the point that, as a matter of principle, all propositions are either synthetic a posteriori or tautologous; synthetic aprioripropositions seem to it to be a logical impossibility.”3 The denial of synthetic apriorisis a major thesis of the logical empiricist position, being found in the writings of most of the leaders of the movement.4 The reason for its importance is fairly clear. It provides a formula on which the empiricists can base their critique of traditional philosophy. To use Ayer's phrase, denial of the synthetic aprioriresults in “the elimination of metaphysics”. The philosophical tradition to which the empiricists are opposed and whose “metaphysics” they wish to eliminate can be called, somewhat loosely, rationalism.