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One True Logic

Dr. Owen Griffiths

Lecturer in Philosophy, UCL and University of Cambridge, and A.C. Paseau, Professor of Mathematical Philosophy, University of Oxford

One True Logic

A Monist Manifesto

  • The first book to defend logical monism against logical pluralism

  • A philosophical introduction to infinitary logic

  • A thorough defence of a particular highly infinitary logic

  • Places the history of logic in conversation with contemporary philosophy of logic, combining historical, philosophical, and technical material throughout

  • One True Logic will familiarise readers with the current state of play in debates around logical consequence, the logical constants, logical form, and logical pluralism

Logical monism is the claim that there is a single correct logic, the ‘one true logic’ of our title. The view has evident appeal, as it reflects assumptions made in ordinary reasoning as well as in mathematics, the sciences, and the law. In all these spheres, we tend to believe that there are determinate facts about the validity of arguments. Despite its evident appeal, however, logical monism must meet two challenges. The first is the challenge from logical pluralism, according to which there is more than one correct logic. The second challenge is to determine which form of logical monism is the correct one.


One True Logic is the first monograph to explicitly articulate a version of logical monism and defend it against the first challenge. It provides a critical overview of the monism vs pluralism debate and argues for the former. It also responds to the second challenge by defending a particular monism, based on a highly infinitary logic. It breaks new ground on a number of fronts and unifies disparate discussions in the philosophical and logical literature. In particular, it generalizes the Tarski-Sher criterion of logicality, provides a novel defense of this generalization, offers a clear new argument for the logicality of infinitary logic and replies to recent pluralist arguments.

Author Information:

Owen Griffiths and A.C. Paseau

Owen Griffiths is a philosopher of logic and language, and a lecturer at University College London and the University of Cambridge. He is the author of several research articles and chapters in collected volumes, and winner of a 2022 Pilkington Prize for outstanding teaching at the University of Cambridge.


A. C. Paseau is the Stuart Hampshire Fellow at Wadham College and Professor of Mathematical Philosophy at the University of Oxford. Author of more than 50 research articles and reviews, he has also edited the 5-volume anthology Philosophy of Mathematics (Routledge 2017) and co-edited the collection Mathematical Knowledge (OUP 2007).

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