Abstract

In this book, Bäck dedicates himself to the logical properties of the qua connective, that is, to put it as does the Leibniz scholar Benson Mates, to “that treacherous little word ‘as’”. This connective is represented in ordinary language by expressions such as “insofar as,” “in virtue of,” “in the sense that,” translating the Greek ᾗ, and the Latin ut, prout, inquantum. Bäck reminds us that, traditionally, “a use of this connective was called reduplication”. The goal of the book is thus to “trace the development of the theory of reduplication... [which] has its roots in various passages where Aristotle discusses qua propositions. Islamic and Latin medieval philosophers then contributed to the topic. From all this there arose a theory of qua propositions, or a theory of reduplication, in the high medieval period ”. Bäck adds that the views of the different philosophers who dealt with reduplication in that period are extremely similar, so that “it makes sense to talk of the rise of a single theory of reduplication”. In fact, quite correctly, he points out that the similarity of these views is due to the use of Aristotle’s work as a common reference point. All these authors “heed what Aristotle says about qua propositions, and attempt to offer analyses that demonstrate the truth of those qua propositions that Aristotle asserts and the validity of inferences involving qua propositions that he maintains”. The problem lying at the heart of all this is that of determination, that is, of the qualification of a sentence by a modifier. Among its applications are the fallacy of secundum quid et simpliciter, the ἔκθεσις of reduplicative propositions, the conversion of reduplicative propositions, the reduplicative syllogistic, and the supposition of terms in qua propositions.