Not by experience alone: Toward a theory of a priori justification

I motivate the need for and begin developing an account of internalist foundationalist a priori justification. This view of a priori justification is committed to the thesis that there is a phenomenon, reason-based intuition or rational insight, which involves the non-inferential and non-empirical (in the sense of relying essentially on sensory experience) acquisition of epistemic justification for beliefs based purely on adequate reflection on or understanding of the concepts, propositions or things that are the objects of beliefs so justified.;In Chapter 1 I motivate the need for an account of a priori justification by considering three arguments against strict empiricism: the generality argument, the argument from modality, and the metajustification argument. I argue that debates between rationalism and empiricism are best understood in the context of foundationalist internalism. I then appeal to plausible commitments of foundationalist internalism in conjunction with plausible theses about the nature of the content of sensory experience to argue that each of the three arguments against strict empiricism is sound, despite recent objections to the contrary. Strict empiricism in conjunction with plausible epistemic principles and assumptions entails skepticism about justification for belief in the majority of propositions of the sciences, logic and mathematics. If one is committed to some version of foundationalist internalism, and skepticism about the majority of general and modal beliefs in science, mathematics and logic is implausible, then one should be committed to the existence of at least some a priori justification.;In Chapter 2 I introduce what I call the "traditional conception of intentionality", which has roots in the phenomenological tradition of Franz Brentano and Edmund Husserl. I characterize this view of the nature of thought, its content and its objects as a version of content internalism and discuss three major implications of the view: that thought is "conception dependent", "existence independent", and admits of "indeterminacy". I consider recent arguments against internalism about content and argue that the conception of intentionality I am developing can be understood in such a way that these arguments do not compromise it. I then argue that certain versions of content externalism involve the denial of the conception dependence, existence independence and indeterminacy of thought advocated by the traditional view. Each of these denials leads to a problem for externalism: the qua problem, the problem of thought about the non-existent, and problems involving knowledge and self-knowledge respectively. This being the case, the traditional conception of intentionality is a plausible version of internalism and represents a significant alternative to externalism about content.;In Chapter 3 I develop accounts of indexical and demonstrative content, and of propositions, all of which are motivated by the traditional conception of intentionality. I argue that the best way for the traditional conception of intentionality to respond to recent arguments against content internalism is by developing an account of indexical and demonstrative intentional content. I offer such an account, then discuss its implications for a neo-Fregean view of propositions.;In Chapter 4 I identify a key desideratum for any account of distinctively epistemic justification, and develop an account of epistemic internalism intended to meet this desideratum. I argue that the primary task in developing an account of epistemic justification is to establish the existence of a modal tie of "making likely" or "probable" between reasons for belief (whether these be "production by reliable cognitive processes" or "internally accessible mental states") and the truth of what is believed on their basis. I then introduce and articulate two notions, the notion of identity-sensitive phenomenology and the notion of an identity-sensitive thought type, as candidates for basic internalist justification. I conclude by attempting to motivate the intuition that experiences with identity-sensitive phenomenology are more likely than not to be instances of identity-sensitive thought types, and that experiences that are identity-sensitive thought types can plausibly be understood as involving the kind of modal tie between reasons and the likely truth of things believed on their basis that the first part of the chapter proposed as a desideratum for accounts of epistemic justification.