Philosophers debate about which logical system, if any, is the One True Logic. This involves a disagreement concerning the sufficient conditions that may single out the correct logic among various candidates. This paper discusses whether there are necessary conditions for the correct logic; that is, I discuss whether there are features such that if a logic is correct, then it has those features, although having them might not be sufficient to single out the correct logic. Traditional rationalist arguments suggest that (...) the necessary conditions of thought are necessary and sufficient conditions singling out the correct logical and mathematical theories. In the contemporary debate, Chalmers advocates a view along this line. Jago, analogously, suggests that the necessary conditions for thought—or, as he calls them, our basic epistemic expectations—single out a family of logical and mathematical theories. Warren and Williamson, on the other hand, argue that there are no necessary conditions of thought. I argue that there are necessary conditions for thought, and these are necessary but not sufficient conditions to be the correct logic; indeed, these are features that all logics—correct or incorrect—share. No view we can understand is ruled out by the necessary conditions for thought, but we cannot understand quite any view. Human linguistic and conceptual abilities are genetically constrained, and these constraints are our best guide to the boundaries of logic. Arguing for this, I tackle two dogmas of modern rationalism: namely, the view that the biological constraints of human cognition have no bearing on the boundaries of the epistemic space, and the view that the boundaries of thought coincide with the boundaries of language. (shrink)

It is customarily assumed that paracomplete and paraconsistent solutions to liar paradoxes require a logical system weaker than classical logic. That is, if a logic is not fragile to liar paradoxes, it must be logically weaker than classical logic. Defenders of classical logic argue that the losses of weakening it outweigh the gains. Advocates of paracomplete and paraconsistent solutions disagree. We articulate the notion of fragility with respect to the liar paradox and show that it can be disentangled from logical (...) strength. Strength and resilience to paradox do not force a trade-off with respect to liars: there can be logics which are not weaker than classical logic and are solid to the liar. (shrink)

In this thesis I defend optimism about philosophical progress, which is a form of anti-exceptionalism about philosophy. Pessimists maintain that philosophy lacks the distinctive features that make science progressive. Optimism maintains that philosophy is like science, in this respect. My argumentative strategy is the following. I review the literature on philosophical progress to identify the feature that, according to pessimists, philosophy lacks. Then, I develop a historical case study to show that philosophy has these features. The goal is showing that (...) philosophy makes progress by pessimistic standards. My strategy is novel because other optimists, including Stoljar and Dellsén, Firing, and Norton, focus on arguing that a certain set of conditions are sufficient for progress, contrary to what pessimists hold. I focus instead on arguing that, contrary to what pessimists hold, philosophy makes progress by their standards. The most common pessimistic argument is the following: first, pessimists argue that consensus is a necessary condition for progress, second, they argue that philosophy is pervaded by disagreement. It follows that philosophy is exceptional. Beebee, Chalmers, Dietrich, Goldberg, and Kornblith employ various versions of this reasoning. Optimistic responses to this argument typically grant the second premise and challenge the first. Instead, I follow Williamson in granting the first premise and challenging the second. My case study focuses on the work of Gottlob Frege, who is widely regarded as one of the founding fathers of analytic philosophy. I argue that there is consensus in contemporary philosophy about some of the views that Frege set forth. In fact, Frege’s case meets not only the pessimistic requirements for progress, Frege also produced all the epistemic goods that are associated to progress by participants in the more general debate about scientific progress. To show this, I review the literature about scientific progress, following Rowbottom’s analysis. Then I analyse various aspects of Frege’s work to show that it meets all the known conditions of progress. Thus, no matter what view about progress is correct, Frege made progress. Having argued that Frege made progress, I generalize my argument by considering three other authors that arguably made progress in the past. Moreover, I consider contemporary debates in contemporary philosophy to argue that philosophy continues to make progress to this day. Finally, I review some of the barriers to progress that seem indeed to be holding back philosophy, and other disciplines. Philosophy made progress in the past and continues to make progress to this day. But not all is good. Having ruled out pessimism about philosophical progress, we are in a better position to see how philosophy, and other disciplines, could be improved. (shrink)