Although traditionally neglected, mathematical diagrams have recently begun to attract attention from philosophers of mathematics. By now, the literature includes several case studies investigating the role of diagrams both in discovery and justification. Certain preliminary questions have, however, been mostly bypassed. What are diagrams exactly? Are there different types of diagrams? In the scholarly literature, the term “mathematical diagram” is used in diverse ways. I propose a working definition that carves out the phenomena that are of most importance for a (...) taxonomy of diagrams in the context of a practice-based philosophy of mathematics, privileging examples from contemporary mathematics. In doing so, I move away from vague, ordinary notions. I define mathematical diagrams as forming notational systems and as being geometric/topological representations or two-dimensional representations. I also examine the relationship between mathematical diagrams and spatiotemporal intuition. By proposing an explication of diagrams, I explain certain controversies in the existing literature. Moreover, I shed light on why mathematical diagrams are so effective in certain instances, and, at other times, dangerously misleading. (shrink)

It is nowadays standard to distinguish between epistemic and metaphysical analyticity. Metaphysical analyticity has been widely rejected, while epistemic analyticity has been widely endorsed. I argue that we also have good reason to reject epistemic analyticity. I do so by considering all the plausible ways of characterizing epistemic analyticity and of drawing the epistemic analytic–synthetic distinction. I argue that on all of them, the distinction fails to carve at the semantic joints. I conclude that there is good reason to think (...) that there is no semantic distinction to be drawn between analytic and synthetic sentences. (shrink)

This work investigates intuitions' nature, demonstrating how philosophers can best use them in epistemology. First, the author considers several paradigmatic thought experiments in epistemology that depict the appeal to intuition. He then argues that the nature of thought experiment-generated intuitions is not best explained by an a priori Platonism. Second, the book instead develops and argues for a thin conception of epistemic intuitions. The account maintains that intuition is neither a priori nor a posteriori but multi-dimensional. It is an intentional (...) but non-propositional mental state that is also non-conceptual and non-phenomenal in nature. Moreover, this state is individuated by its progenitor, namely, the relevant thought experiment. Third, the author provides an argument for the evidential status of intuitions based on the correct account of the nature of epistemic intuition. The suggestion is the fitting-ness approach: intuition alone has no epistemic status. Rather, intuition has evidentiary value as long as it fits well with other pieces into a whole, namely, the pertinent thought experiment. Finally, the book addresses the key challenges raised by supporters of anti-centrality, according to which philosophers do not regard intuition as central evidence in philosophy. To that end, the author responds to them, showing that they fail to affect the account of intuition developed in this book. This text appeals to students and researchers working in epistemology. (shrink)

Agents can think using concepts they do not fully understand. This paper investigates the question “Under what conditions does a thinker fully understand, or have mastery of, a concept?” I lay out a gauntlet of problems and desiderata with which any theory of concept mastery must cope. I use these considerations to argue against three views of concept mastery, according to which mastery is a matter of holding certain beliefs, being disposed to make certain inferences, or having certain intuitions. None (...) of these attitudes is either necessary or sufficient for mastery. I propose and respond to objections to my own recognition view of the conditions under which a thinker has mastery of a concept. (shrink)

In this paper, we explore the traditional conception of a prioricity as epistemic independence of evidence from sense experience. We investigate the fortunes of the traditional conception in the light of recent challenges by Timothy Williamson. We contend that Williamson’s arguments can be resisted in various ways. En route, we argue that Williamson’s views are not as distant from tradition as they might seem at first glance.

Agustín Rayo’s The Construction of Logical Space offers an exciting and ambitious defense of a broadly Carnapian approach to metaphysics. This essay will focus on one of the main differences between Rayo’s and Carnap’s approaches. Carnap distinguished between analytic, a priori “meaning postulates”, and empirical claims, which were both synthetic and knowable only a posteriori. Like meaning postulates, they determine the boundaries of logical space. But Rayo is skeptical that the a priori/a posteriori or analytic/synthetic distinctions can do the work (...) Carnap wanted them to, so unlike meaning postulates, ‘just is’-statements aren’t assumed to be analytic or knowable a priori. This essay will concern the epistemology of ‘just is’-statements in Rayo’s picture. If not by a priori reflection, how can we determine which ones to accept? I’ll distinguish two competing strands in Rayo’s work. The less radical, Lewisian strand holds that the question of whether to accept a ‘just is’-statement can be addressed in a neutral, non-question-begging way, by a kind of cost-benefit analysis. The more radical, Kuhnian strand holds that there can be no ‘just is’-statement-independent, rational choice of which ‘just is’-statements to accept. I argue that Rayo faces strong internal pressure to adopt the Kuhnian picture. While it is possible for Rayo to resist these Kuhnian pressures, natural strategies for doing so leave his view more similar to Carnap’s than the above gloss suggested. (shrink)

Contemporary epistemologists typically define a priori justification as justification that is independent of sense experience. However, sense experience plays at least some role in the production of many paradigm cases of a priori justified belief. This raises the question of when experience is epistemically relevant to the justificatory status of the belief that is based on it. In this paper, I will outline the answers that can be given by the two currently dominant accounts of justification, i.e. evidentialism and reliabilism. (...) While for the evidentialist, experience is epistemically relevant only if it is used as evidence, the reliabilist requires that the reliability of the relevant process depends on the reliability of experiential processes. I will argue that the reliabilist account accommodates our pre-theoretic classifications much better. In the final part of my paper I will use the reliabilist criterion to defend the a priori—a posteriori distinction against recent challenges by Hawthorne and Williamson. (shrink)