Schlick and Wittgenstein: The Theory of Affirmations Revisited

This talk broaches one aspect of the complex and far-reaching issue of the philosophical relationship between the Vienna Circle and Wittgenstein. I will explore whether recent advances in Schlick and Wittgenstein scholarship allow an at least partial redemption of what has long been considered a theoretical misadventure on the part of Schlick. Viewed from the perspective of the epistemology of science, Schlick’s theory of affirmations was badly mistaken. Schlick meant affirmations to be observation statements that were not identical with the protocol statements recordable by scientists in the course of their work. Conceived of as statements that were incorrigible—albeit only if affirmed sincerely—they were held to constitute a class (the only one) of synthetic statements where understanding of their sense coincided with recognition of their truth. This remarkable characteristic of affirmations was explained by them employing (i) indexical expressions that were held to be irreplaceable by coordinate expressions or proper names and (ii) descriptive expressions the use of which was not constrained by prior usage but only the user’s intentions at the time. Patently, Schlick’s theory was unable to contain, let alone resolve, the tension between the subjective certainty affirmations provided and the objective legitimation of scientific knowledge claims they aimed for. Interpreters either rejected the theory wholesale or saved only part of it for the price of discarding some other property that affirmations supposedly possessed. The question arises whether Schlick’s theory should be considered from an altogether different perspective. First note that Schlick repeatedly addressed as pertinent to the issue of “the foundation of knowledge” the question of the criterion of truth and the opposition between the correspondence and coherence conceptions—when, arguably, the issue of truth was not on the agenda of his physicalist opponents. Then note that for Schlick it was an unquestioned given that there existed such certain and incorrigible foundations of human knowledge—that science did not provide one was of no consequence. Thirdly note that since becoming acquainted with Wittgenstein’s Tractatus Schlick’s philosophical focus underwent a gradual but profound change. Schlick was not the only philosopher of his time who insisted that knowledge in some sense entailed certainty. In his Problems of Philosophy Russell regarded scientific knowledge as merely probable opinion. But Wittgenstein’s influence looms largest here: after his return to philosophy—prompted largely by Schlick—his concerns long centered on (besides mathematics) what we could not be mistaken about, immediate experience, and its relation to human discourse generally. The task of determining which of Wittgenstein’s intermediate insights towards his mature views, recorded in various places, were communicated to Schlick—and precisely when—has been lightened by recent archive work by Mathias Iven and Juha Manninen. Using these and longer established sources my talk will plot Schlick’s views as expressed in his publications against Wittgenstein’s documented communications to see whether Schlick’s affirmations reflect Wittgenstein’s evolving views and can be made better sense of in this context.