Is Bayesianism Inconsistent with Empiricism?

Dr. Bryan Pickel (University of Edinburgh)

Tues 3 Jun, 5.00pm
Room 246, second floor, Senate House, WC1

Bryan Pickel (Edinburgh)

Is Bayesianism Inconsistent with Empiricism? (with Moritz Shulz, LOGOS, Barcelona)

Abstract: Quine's "Two Dogma’s of Empiricism" offered a powerful critique of a traditional conception of the a priori, according to which a priori knowledge is a kind of epistemic necessity that can be known regardless of which experiences one has. A priori knowledge is "absolutely independent of all experience" (Kant 1787, B3). Quine's challenge rested upon two key premises supported by examples from the history of science: (1) any statement may be held true "come what may" and (2) no statement is immune to revision in light of new experience. Given the traditional conception of the a priori, the first claim entails that every statement is knowable a priori and the second claim entails that no statement is knowable a priori. Chalmers (2011, 2012) has recently developed a seemingly compelling challenge to both premises. This challenge purports to undermine the first premise by showing that rationality demands that agents reject certain statements in light of evidence. It purports to undermine the second premise by exhibiting a sentence that is immune to revision in light of new empirical information. The critique is particularly threatening because it rests on only one Bayesian premise, that upon acquiring evidence E, a rational agent will update her credence in any statement S to equal her prior conditional credence in S given E. By carefully examining Quine’s argument, we show that Chalmers's criticisms misfire. First, we show that adopting Bayesian conditionalization actually reinforces the premise that a rational agent may hold true any statement come what may. We then argue that Chalmers has not exhibited a statement that is immune to revision. Finally, we examine some consequences of these results for other aspects of Chalmers's philosophy, in particular, his "front-loading" arguments.
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Summer 2014 Series