Is There a Single “True” Logic?

Abstract This review compares two recent books, One True Logic: A Monist Manifesto, by Owen Griffiths and A. C. Paseau; and Essay on the Principles of Logic: A Defense of Logical Monism, by Michael Wolff, both professing to be defenses of logical monism. Logical pluralism is the view that differing systems of logic may be equally defensible, even though they differ on which arguments should be judged valid; logical monism is the view that only one logic is ultimately “correct.” Despite their shared conclusions, the two books reach that conclusion in strikingly different ways. The review is critical of One True Logic for dismissing “non-classical” logics out of hand, as if it were a foregone conclusion that the one correct logic is truth functional. That book is also criticized for giving specious arguments against logical pluralism. The review praises Essay on the Principles of Logic for having a more satisfactory approach. That book begins by distilling out what Kant would call a canon of pure logic. It then shows that the various logics motivating the argument for pluralism (including truth functional logic) can be explained as special applications (organons) subsumed under that broadly general canon.