La prima inferenza. L’abduzione di C.S. Peirce fra scienza e diritto

In a clear, plain, and direct style, Giovanni Tuzet has written a very compelling work on Peirce’s abduction. The book is an elaboration of his PhD dissertation’s second part, and it is divided into two parts. The first (Logic of Abduction) consists of six chapters in which Tuzet presents not only Peirce’s abduction, but also Peirce’s conception of logic as a normative science, deduction, induction, and the role of abduction in the practice of Law. The second part (Philosophy of Abduction) consists of four chapters in which the author ventures deeper into philosophical issues such as causality, perception, proof, and truth. The book concludes with reflections on the relationship between abduction and pragmatism. On the same issue, each chapter is divided in sections, each dealing with some specific topic, and summing up a total of 64 throughout the book.

Tuzet reconstructs Peirce’s abduction and philosophy of logic from Peirce’s published works and a vast, impressive secondary bibliography of multiple Peircean scholars. In relation to it, Tuzet adopts an ‘ecumenical’ and conciliatory position, collecting and summarizing their commentaries, only giving some critical remarks about his countrymen Eco, Bonfantini, and Proni. In addition, Peirce’s ideas are defended and compared with many contemporary philosophical problems, such as Goodman’s new riddle of induction (p. 184–85), direct and indirect theories of perception (chapter 8), several theories of truth (chapter 10), Searle’s theory of speech acts, etc.

Moreover, Tuzet introduces several attractive ideas when seeking to clarify abduction; for instance, the idea of projectual abduction. The purpose of this kind of abduction is not to explain a series of facts, but to infer the best means for a given end, and this is used in technological innovation, artistic and intellectual creation, commercial activity, and political and juridical action (p. 113–14). Another idea Tuzet proposes is related with the classification of abduction as ordinary and extraordinary (p. 4, 59, 79–80, 97–98). In ordinary abduction we have at our disposal the ‘rule’ for inferring the ‘case’; which is something we do not have in extraordinary abduction. This leads him to consider the novelty as absolute in an extraordinary abduction because a new type is proposed, and to regard it as relative in an ordinary one because a new token of a known case is identified (p. 99).

Chapter eight, “Abduction and Perception,” is a truly remarkable chapter. Here Tuzet proposes that perceptual abduction has two elements: one classificatory (the comprehension of predicates permits identification) and other explanative (from sensations the presence of an object is inferred). Tuzet prefers to talk of ‘classification’ and not of ‘recognizance’, and this allows him to make a triple distinction in perception: a) a new token of a known type; b) a variant token from a known type; and c) a token from an unknown type (p. 238). These distinctions are related with his ordinary and extraordinary abductions, and so he presents, on the one side, extraordinary perception as an unknown combination of known characters, and on the other side, perception of an object in a new manner (modification of the type), and perception of a new object (p. 255). In addition he presents an interesting discussion of Peirce’s theory of perception and the distinctions between percept, perceptual fact, perceptual judgment, and percipuum. In contrast with contemporary theories (e.g. Musgrave, Putnam), Tuzet says that Peirce has a direct and indirect account of perception: it is direct because the percept has sensible features and is dyadic; and it is indirect because the perceptual judgment has conceptual features and is triadic (p. 250–52).

The difference Tuzet draws between informativity and ampliativity is equally remarkable. According to Tuzet, deduction can be informative notwithstanding its not being ampliative (p. 150). That is to say, from a logical point of view, deduction makes...