Hume Society Guest Speaker: Christopher Peacocke, Columbia University

The A Priori, Metaphysics, and Objective Justification: A Unification

I start with a puzzle about the traditional notion of the a priori. There are two resources we can bring to solving the puzzle. One of these resources involves the development of a notion of an Objective Justificational Structure. The proposed solution to the puzzle suggests there are two fundamentally different kinds of a priori proposition. Crucial to the solution to the puzzle is the distinction between an Objective Justificational Structure and the relations in which a thinker may stand to it. This distinction can also be applied more widely, to address issues about the a priori, including the role of perception and much else that seems empirical in the justification of propositions in domains, from arithmetic to ethics, in which fundamental knowledge is plausibly classified as a priori. A position emerges that can be classified as a Fourth Way, distinct from the Three Ways presented in the writings of Carnap, Quine, and Gödel. The emerging position has Kantian overtones, but without the transcendental idealism.