Timothy Williamson’s Tetralogue is precisely an investigation on the merits and limits of rational debate. Four people holding very different views sit across each other in a train and discuss a wide range of topics, such as the existence of witchcraft, the superiority and falibilism of scientific reasoning, whether anyone can ever be sure to really know anything, what it means for a statement to be true, and many others. As one of the most influential philosophers currently in activity, Williamson is well placed to give the reader an overview of some of the main debates in recent philosophy, as his characters debate their views.

Disagreement in debates and discussions is an interesting phenomenon. On the one hand, having to justify your views and opinions vis-à-vis those who disagree with you is perhaps one of the best ways to induce a critical reevaluation of these views. On the other hand, it is far from clear that a clash of views will eventually lead to a consensus where the parties come to hold better views than the ones they held before. This is one of the promises of rational discourse, but one that is all too often not kept. What to do in situations of discursive deadlock?

I've been asked to write a review of Williamson's brand new book Tetralogue for the Times Higher Education . Here is what I've come up with so far. Comments are very welcome, as I still have some time before submitting the final version. (For more background on the book, here is a short video where Williamson explains the project.)

Bob represents those who hold what could be describe as ‘ancestral’ modes of thinking, including superstition, belief in witchcraft and so forth; Sarah is the staunch child of the Enlightenment, firmly convinced of the superiority of scientific knowledge over Bob’s ancestral beliefs; Zac is the relativist who abhors absolute views, and rejects the idea that anything can be true or false simpliciter; Roxana, a latecomer in the conversation, is the most unpleasant of them all (not that any of the other three is particularly pleasant), and represents rationality taken to its limit: she is the one who pursues the logical conclusions of each position to its (sometimes absurd) limits. As these people try to resolve their differences and convince each other of their own worldviews, Williamson explores the limits of rational debate and disagreement.

What is perhaps most noteworthy about this book is the dialogical form adopted. The dialogue as a literary form marked the very birth of Western philosophy with Plato’s dialogues, which in all honesty remain unsurpassed when it comes to complexity, philosophical sophistication, and pure literary beauty (the Gorgias is my favorite). In the circa 2.500 years since, a number of philosophical works have adopted the dialogical form, in some periods more than in others: dialogues were particularly important in the Latin medieval tradition, and the early modern period saw a resurgence of the genre with Leibniz, Hume, and Diderot, among others. (See V. Hösle, The Philosophical Dialogue, 2012.) But for the most part, philosophical literary forms such as the philosophical essay tend to be superficially non-dialogical, while in practice often corresponding to ‘internalized’ dialogues where arguments, counter-arguments, counter-counter-arguments etc. are presented by one and the same voice. Indeed, in recent decades no prominent philosophical work written in dialogical form seems to have appeared, with the very notable exception of Lakatos’ Proofs and Refutations (1976).