Studies in History and Philosophy of Science 48 (2014) 10e19 Contents lists available at ScienceDirect Studies in History and Philosophy of Science journal homepage: www.elsevier.com/locate/shpsa Realism, functions, and the a priori: Ernst Cassirer’s philosophy of science Jeremy Heis Department of Logic and Philosophy of Science, University of California, 763 Social Sciences Tower, Irvine, CA 92697-5100, USA article info abstract Article history: This paper presents the main ideas of Cassirer’s general philosophy of science, focusing on the Received 20 July 2012 two aspects of his thought thatdin addition to being the most central ideas in his philosophy of Received in revised form sciencedhave received the most attention from contemporary philosophers of science: his theory of the 9 August 2014 a priori aspects of physical theory, and his relation to scientific realism. Available online Ó 2014 Elsevier Ltd. All rights reserved. Keywords: Ernst Cassirer; Realism; A priori; Conventionalism When citing this paper, please use the full journal title Studies in History and Philosophy of Science Ernst Cassirer, the Neo-Kantian trained philosopher whose change, the nature of experimentation, the a priori elements in wide-ranging work spanned the first four decades of the twentieth scientific theories, and the application of mathematics in physical century, was one of the most prominent and respected philoso- science. Cassirer’s commitment to a philosophy of science that phers of science of his time. Easily the most subtle and mathe- engaged with cutting edge science ran deep and was widely matically well-informed of the Neo-Kantians, he was among the known. For example, as a letter from Hans Reichenbach makes vanguard of early twentieth century philosophers seeking to un- clear, Cassirer was the only philosopher to sign onto a petition, derstand the philosophical significance of the revolutionary ad- composed by Reichenbach in 1931 and co-signed by Hilbert and vances made in logic, mathematics, and physics. Not only did Einstein, petitioning the German government to create a chair in Cassirer write some of the earliest philosophical works on general the philosophy of science.4 relativity and quantum mechanics,1 but he was one of the first It is not surprising, then, that Cassirer’s work has been studied German academic philosophers to give serious attention to Rus- extensively by historians of philosophy. But several prominent sell’s logicism and the new logic,2 Dedekind’s foundations of philosophers of science have also recently turned their attention to arithmetic, and to Hilbert’s axiomatic foundation of geometry.3 Cassirer, finding in his writings philosophical positions that only Cassirer also wrote extensively on some of the perennial issues in now many years later are receiving sustained philosophical inter- general philosophy of science: realism, confirmation, theory est. For example, many defenders of “structural realism” within the philosophy of science have explicitly pointed to Cassirer’s writings 5 E-mail address: [email protected]. as an historical anticipation of their own theories, and Michael 1 Cassirer Einstein’s Theory of Relativity [ETR](1923 [1921]), Determinism and Indeterminism in Modern Physics (1954 [1936]). Throughout this paper, I will adopt 4 Letter from Reichenbach to Cassirer, 5 June 1931, HRd025d11d04; 15 June the following practices. If there is a translation listed in the bibliography of a work 1931, HRd025d11d 03. These letters are reproduced in the CD-Rom accompa- not written in English, I will quote from the listed translation (except for occasional nying Cassirer (2009). corrections that I make silently). Page citations are from the listed translations 5 See French (2001), pp. 2e7, 14; French and Ladyman (2003), pp. 38e41; Gower unless otherwise noted. Translations from works not in English for which there is (2000), pp. 87e95; Massimi (2010). Structural Realism is often split into “epistemic” no English translation in the bibliography are all my own. and “ontic” versions. French and Ladyman see in Cassirer an anticipation of ontic 2 Cassirer (1907). structural realism; Gower and Massimi see in him an anticipation of epistemic 3 Cassirer, Substance and Function [SF](1923 [1910]), Chap. 2e3. structural realism. http://dx.doi.org/10.1016/j.shpsa.2014.08.003 0039-3681/Ó 2014 Elsevier Ltd. All rights reserved. J. Heis / Studies in History and Philosophy of Science 48 (2014) 10e19 11 Friedman has identified Cassirer as an inspiration for the philoso- Philosophy of Symbolic Forms in 1923, these ideas were broadened phy of science defended in his book Dynamics of Reason (2001, in two ways. First, Cassirer came to appreciate that the various pp. 65e8; 2005). special sciences have their own distinct methodologies that need to Despite this attention, there is still disagreement among phi- be investigated individually, whereas the philosophy of science losophers over the interpretation of many of the main ideas of presented in SF is almost exclusively concerned with physics. In Cassirer’s philosophy of science. For example, one of the most particular, in The Logic of the Cultural Sciences (2000 [1942]), Cas- striking and suggestive features of his philosophy is its conception sirer argues that cultural sciences such as history can attain ob- of the a priori. Some interpreters (Richardson, 1998, chap. 5; jectivity despite not relying on the experimental and mathematical Ryckman, 2005, chap. 2) have claimed that Cassirer’s theory of the a methods characteristic of physics. Second, Cassirer came to believe priori is an anticipation (and, indeed, the historical source) of the that the kind of human activities investigated by cultural sciences theory of the relativized, but constitutive a priori later articulated such as linguistics, anthropology, history, and comparative religion by Reichenbach (who was, after all, Cassirer’s student in Berlin). each make possible a distinct kind of objectivity. These various According to Michael Friedman, however, the a priori elements that ways of constituting objectivity Cassirer calls “symbolic forms,” and Cassirer claims to find in science are absolute, but not relative, and he argues that myth, art, and language are symbolic forms along- are merely regulative, not constitutive (Friedman, 2000, 115ff). Alan side the symbolic form of knowledge (which is the form exhibited Richardson, on the other hand, argues that Cassirer, in trying (un- most perfectly by science). The “functionalist” account of knowl- successfully) to integrate a theory of the constitutive, relative a edge that I describe in Section 1 and the account of a priori ele- priori with a theory of the regulative, absolute a priori, succeeds ments that I describe in Section 2 are then carried over to these only in presenting a “plurality of inconsistent accounts” other symbolic forms, though of course in significantly modified (Richardson, 1998, p. 136). Last, Thomas Ryckman argues that for ways. Unfortunately, given the confines of a paper, I cannot do any Cassirer (in his book Einstein’s Theory of Relativity) the principle of more than mention the wider vistas of Cassirer’s philosophy of general covariance is both constitutive and regulative (2005,p. symbolic forms (though I believe that understanding Cassirer’s 46)dthus agreeing with Richardson (against Friedman) that there philosophy of (mathematical and physical) science is an ideal way are constitutive a priori principles in Cassirer’s theory, while dis- of working one’s way into this larger system). agreeing with Richardson that this amounts to any kind of tension in Cassirer’s thinking. Similar issues arise in discussions of Cas- 1. “Substanzbegriff” and “Funktionsbegriff” sirer’s relation to realism. As French, Ladyman, and Massimi all recognize,6 there is a clear (though hard to articulate) tension be- The animating idea in Cassirer’s philosophy of sciencedindeed, tween a reading of Cassirer’s philosophy that brings him close to in his theoretical philosophy in generaldis the contrast between contemporary structural realism, and Cassirer’s own rejection of substance-concept [Substanzbegriff] and function-concept [Funk- realism in favor of idealism. tionsbegriff], a contrast that provides the title for his first system- The goal of this paper is to present the main ideas of Cassirer’s atic book-length work in the philosophy of science.7 Cassirer means general philosophy of science. In particular, I will present the this contrast to cover a number of different interrelated epistemic, contours of the two aspects of his thought thatdin addition to logical, and metaphysical contrasts. Of these many uses, the most being among the most central ideas in his philosophy of scien- fundamental use that Cassirer makes of “Substanzbegriff” and cedhave received the most attention from contemporary philos- “Funktionsbegriff” is epistemological and Kantian: it contrasts ophers of science: his theory of the a priori, and his relation to philosophical views that overlook the epistemic preconditions of scientific realism. I will argue (against Friedman) that Cassirer’s various kinds of knowledge, with those that recognize the “func- theory assigns both constitutive and regulative, relative and abso- tions” [or “preconditions”] that make certain kinds of knowledge lute, roles for a priori representations. These a priori representa- possible.8 To oppose the point of view of “Substanzbegriff,” then, is tions help explain the possibility of scientific objectivity and thus to oppose various