RB 65

whereupon he rejects the possibility of establishing a valid synthetic a priori, as the synthetic a priori is a proposition that in order to preserve its analytical certainty must be devoid of any material content and therefore only concerned with form.281 The corollary to this argument is that the self-contradictory nature of the synthetic a priori judgment prevents it from establishing any judgment or proposition that is a priori valid and true about this external world of objects. Because the a priori part of the synthetic a priori judgment is decided on material grounds, rather than on purely formal grounds (which constitutes the definition of the a priori). And furthermore, when dealing with the synthetic part of the synthetic a priori judgment it turns out that the synthesis, the a posteriori part, must itself be decided on formal grounds, rather than on purely material grounds, since the formal structure that supports the formal validity of the deductive demonstration simultaneously constitutes the facticity upon which the a posteriori itself must rest upon. Both when analyzing the analytic and the synthetic elements of the synthetic a priori we have contradictions. In the first case, an analytic truth is supposed to be decided upon empirical grounds, and consequently that which holds a priori (analytically) is supposed to be verified synthetically by reference to facts, rather than being validated through demonstrative analysis. In the second case, a synthetic truth is supposed to be logically demonstrated on logical grounds, and consequently that which holds a posteriori is supposed to be validated analytically by reference to a logical demonstration, rather than to be verified by reference to facts. In either case one still has to resort to a transcendental argument in order to: a) transcend the insurmountable barrier between the contradictory opposite forms of knowledge, formal certainty and material certainty; b) unite them into to one consistent whole; a ca l l f o r s c i e n t i f i c p u r i t y 129 281 E.g., Hägerström,“Ett Hägerström brev,” pp. 88-89.This article contains a letter Hägerström wrote on4 January 1931 to Arnold Sölvén. In this letter, Hägerström explains his philosophy with the aim disproving claims that he was an epistemological subjectivist.