Reasons for Logic, Logic for Reasons

by Robert B. Brandom

Reasons for Logic, Logic for Reasons presents a philosophical conception of logic—“logical expressivism”—according to which the role of logic is to make explicit reason relations, which are often neither monotonic nor transitive. This conception of logic reveals new and enlightening perspectives on inferential roles, sequent calculi, representation, truthmakers, and many extant logical theories.

The book shows how we can understand different metavocabularies as making explicit the same reason relations, namely normative-pragmatic, alethic-representational, logical, and “implication-space” metavocabularies. This includes a philosophical account of the pragmatic role of reason relations, treatments of nonmonotonic and nontransitive consequence relations in sequent calculi, a correspondence between these sequent calculi and variants of truthmaker theory, and the introduction of a novel kind of formal semantics that interprets sentences by assigning inferential roles to them. The book thus offers logical expressivists and semantic inferentialists new ways to understand logic, content, inferential roles, representation, and reason relations.

This book will appeal to researchers and graduate students who are interested in the philosophy of logic, in reasons and reasoning, in theories of meaning and content, or in nonmonotonic and nontransitive logics.

354 pages, Hardcover

Published May 20, 2024

About the author

Robert B. Brandom is Distinguished Professor of Philosophy at the University of Pittsburgh and a Fellow of both the American Academy of Arts and Sciences and the British Academy. He delivered the John Locke Lectures at the University of Oxford and the Woodbridge Lectures at Columbia University. Brandom is the author of many books, including Making It Explicit, Reason in Philosophy, and From Empiricism to Expressivism.

Reviews

[Joey Z · Rating 5 out of 5]

I took a break halfway through after realized I had to brush up on logic. Now that I am more familiar with truth-maker semantics and some of the more contemporary developments that were gaps in my knowledge, I am able to really appreciate the full scope of this book.

The innovations here pursues an intuition and an impulse many philosophers have—that different philosophical perspectives share a common form. Brandom and Hlobil elaborate in incredible detail, thanks to the robustly expressive capacity of logic, how metavocabularies of the discursively normative pragmatic variety and the alethically modal semantic variety are two sides of the same coin. Not only that, but how implication space semantics “sits” above both strategies and the logical vocabulary intrinsic to both that “sits” below are sufficient to make clear just about any claim or worldly-proposition in terms of their reason-relations. (In a way, this is the greatest development in transcendental philosophy since Deleuze.)

For that reason, it is not so bold to claim that it is reason-relations all the way down. Even more boldly, not only do Brandom and Hlobil ask one to put their money where their mouths are, they also give you the tools do so.

In many ways, this book is continuous to the ‘minimal’ system of philosophy that Brandom has been developing for his entire career, but helps to fit the crown jewel in that system. And while I am unapologetically an apologist for Brandom, this has really sealed the fact for me that he is one of the canonical greats—and I am beyond honored to have shared a city and university with him.

Hlobil for that matter is an incredible logician who has managed to make many things clear to me. I don’t think I ever understood the ‘appeal’ of the different logics he has contextualized until I read him wave a magic wand with implication space semantics and rational forms. His chapters were incredibly difficult for the simple fact that he has a clear mastery over so many varieties of logic that seemed to be broadly ‘incompatible’ with each other, but nonetheless driven a re-enchantment with logic for me.

Semantically, starting with primitive notions of consequence and incompatibility has really done wonders for me appreciating how logic works. Starting logic with truth-values as something we cannot help but assume, never really made sense to me with my ‘continental’ inclination. But dipping my toes into the sequent calculi world, particularly the bilateral normative variety in this book has made it easier for me to grasp why certain conventions and rules are what they are in the logics they subsist in.

While Scholasticism has been exhausted and while German Idealism may never be completed—as far as I am concerned logic has been completed in a way that allows any possible logic (to my knowledge) to be contextualized within the ideas put forward in this book. There are many questions I have that are left unanswered, but at least I have more interesting ways to answer them.