The debate between exceptionalists and anti-exceptionalists about logic is often framed as concerning whether the justification of logical theories is a priori or a posteriori (for short: whether logic is a priori or a posteriori). As we substantiate (S1), this framing more deeply encodes the usual anti-exceptionalist thesis that logical theories, like scientific theories, are abductively justified, coupled with the common supposition that abduction is an a posteriori mode of inference, in the sense that the epistemic value of abduction is (...) (and, indeed, must be) a posteriori. In past work, however, we have argued that this common supposition is incorrect: abduction is an a priori mode of inference, in the sense that the epistemic value of abduction is (and indeed, must be) a priori (Biggs and Wilson 2017a, 2017b, 2019). After sketching our two main argumentative strategies for this conclusion (S2), we go on (S3) to consider its import on the proper understanding of anti-exceptionalism about logic. (shrink)

Amie Thomasson has defended a view called Easy Ontology, according to which most ontological questions can be answered straightforwardly using conceptual truths and empirical knowledge. Furthermore, she claims that this deflationary meta-ontology does not commit her to any form of anti-realism. In this paper I identify a problem with Thomasson’s account of quantification, according to which everything we quantify over falls under a sortal. Thomasson’s defence of the easiness of answering ontological questions relies on a certain thesis about the hierarchical (...) order of sortals, but the case for the compatibility of Easy Ontology and realism suggests that this thesis is actually false. (shrink)

How should modal reasoning proceed? Here we compare abduction-based and conceiving-based modal epistemologies, and argue that an abduction-based approach is preferable, and by a wide margin.

Many who take a dismissive attitude towards metaphysics trace their view back to Carnap’s ‘Empiricism, Semantics and Ontology’. But the reason Carnap takes a dismissive attitude to metaphysics is a matter of controversy. I will argue that no reason is given in ‘Empiricism, Semantics and Ontology’, and this is because his reason for rejecting metaphysical debates was given in ‘Pseudo-Problems in Philosophy’. The argument there assumes verificationism, but I will argue that his argument survives the rejection of verificationism. The root (...) of his argument is the claim that metaphysical statements cannot be justified; the point is epistemic, not semantic. I will argue that this remains a powerful challenge to metaphysics that has yet to be adequately answered. (shrink)

Here we challenge the orthodoxy according to which abduction is an a posteriori mode of inference. We start by providing a case study illustrating how abduction can justify a philosophical claim not justifiable by empirical evidence alone. While many grant abduction's epistemic value, nearly all assume that abductive justification is a posteriori, on grounds that our belief in abduction's epistemic value depends on empirical evidence about how the world contingently is. Contra this assumption, we argue, first, that our belief in (...) abduction’s epistemic value is not and could not be justified a posteriori, and second, that attention to the roles experience plays in abductive justification supports taking abduction to be an a priori mode of inference. We close by highlighting how our strategy for establishing the a priority of abduction positively contrasts with strategies in Bonjour (1998), Swinburne (2001), and Peacocke (2004) aiming to establish the a priority of certain ampliative modes of inference or abductive principles. (shrink)