ORIGINAL ARTICLE Friedman on Implicit Definition: In Search of the Hilbertian Heritage in Philosophy of Science Woosuk Park Received: 25 April 2010 / Accepted: 26 May 2011 / Published online: 13 September 2011 Ó Springer Science+Business Media B.V. 2011 Abstract Michael Friedman’s project both historically and systematically testifies to the importance of the relativized a priori. The importance of implicit definitions clearly emerges from Schlick’s General Theory of Knowledge. The main aim of this paper is to show the relationship between both and the relativized a priori through a detailed discussion of Friedman’s work. Succeeding with this will amount to a contribution to recent scholarship showing the importance of Hilbert for Logical Empiricism. 1 Introduction Michael Friedman has been prominent in recent reevaluations of logical positivism. His project both historically and systematically testifies to the importance of the relativized a priori. The importance of implicit definitions clearly emerges from Schlick’s General Theory of Knowledge. The main aim of this paper is to show the relationship between both and the relativized a priori through a detailed discussion of Friedman’s work. Succeeding with this will amount to a contribution to recent scholarship showing the importance of Hilbert for Logical Empiricism. Friedman details how the relativized a priori was viewed by the leading logical positivists, Reichenbach, Schlick, and Carnap. Curiously enough, however, Friedman is rather reticent in presenting his own views about the Hilbertian heritage of logical positivism. To what extent and in what respects were logical positivists indebted to Hilbert? In particular, what exactly did they learn from the notion of implicit definition as the core of Hilbert’s axiomatic method? To what extent does the history of implicit definitions overlap with that of the relativized W. Park (&) Humanities and Social Sciences, Korea Advanced Institute of Science and Technology, 373-1 Guseong Dong, Yuseong Gu, Daejeon 305-701, S. Korea e-mail: woosukpark@kaist.ac.kr 123 Erkenn (2012) 76:427–442 DOI 10.1007/s10670-011-9297-8