In this course we will work through John Buridan's *Sophismata* (sophisms or paradoxes). We will use G. Klima's English translation of *Summulae de Dialectica*, 2001. We will concern ourselves primarily with the eighth chapter on self-reference, but we will also work through some of the first and second chapters on signification and truth. The most famous of the sophisms to the present-day philosopher is the so-called liar paradox, 'I am now uttering a falsehood'. There has been much recent discussion of such paradoxes and Buridan provides his own solution of them. To put things into perspective, we will compare Buridan's treatment of the sophisms to some contemporary solutions.

What does it mean to persist, to exist from one time to another while undergoing change? Is the future open or indeterminate, and if so, how? Is tense a primitive, ineliminable notion? Is time travel possible, or does the idea face insuperable difficulties? In answering these questions and more, we will look at competing views about:

- persistence
- the open future
- tense
- the possibility of time travel

For each of the topics we will look at seminal essays from each side of the debate to gain a fair perspective on the relevant issues.

This course provides an introduction to non-classical (propositional) logic. We will look at both the formal (model- and proof-theoretic) aspects of non-classical logics, as well as their philosophical applications and motivations. Some of the logics covered include: intuitionistic, relevant, many-valued, paraconsistent, and counterfactual or conditional logics. One aim of the course is to gain familiarity with some of the ways formal methods are applied in philosophy, and what the advantages, disadvantages and limitations are of the use of such methods. For instance, we will look at logics for reasoning about conditional obligations; that is, obligations one has only if certain conditions hold. For example, we are not obligated to punish Smith *unless* he does something punishable.

The study of modality, of what is possible and necessary, has been an important topic at least since Aristotle who systematized basic modal reasoning. Modal arguments have been used, e.g., to prove the existence of God, to show that determinism is incompatible with free will, and to show that two distinct things may occupy the same spatial region at precisely the same time. Modality has also been used to analyze a wide variety of philosophically central concepts including knowledge, causation, and natural language conditionals.

This course will be devoted to David Lewis's fascinating and influential book "On the Plurality of Worlds" (1986). This book is Lewis's most sustained defense of modal realism, the view that (i) possible worlds exist and that they are as real (concrete, of the same kind) as our own, and (ii) that modality is grounded in these worlds. One of the main virtues of Lewis's modal realism is that is the only well-developed account of modality that reduces modal notions like possibility to non-modal ones. This is arguably virtuous, as the non-modal notions Lewis appeals to are thought to be much less mysterious than the modal ones they replace.

This course provides an introduction to non-classical (propositional) logics and their applications, with a focus on conditionals. Some of the logics covered include logics of counterfactual conditionals, as well as relevant, many-valued, and paraconsistent logics. We will look at both the formal (semantic and proof-theoretic) aspects of non-classical logics, as well as their philosophical applications and motivations. In particular, we will evaluate how well non-classical approaches to the semantic paradoxes fair against each other.