The Logic of the Plausible and Some of its Applications

So simple and imperfect as it may appear this book has made use of knowledge on invention and discovery accumu lated during a lifetime. Those persons who would be tempted to emphasize only its imperfections should read the correspondence exchanged between Cantor and Dedekind at the end of the nineteenth century; they would then realize how difficult it was, even for an outstanding man, the creator of the set theory, to propose impeccable results in a completely new field. The field I have chosen here is plausibility. I have proposed an intuitive, some would say a naive, presentation as I want to reach as large an audience as possible and because I personally believe that it is easier to axiomatize a mathematical theory precisely than to dis cover it and enunciate its key theorems. Professor Polya said: "The truly creative mathematician is a good guesser first and a good prover afterward. " For centuries a formalized generalized logic was found necessary and many attempts have been made to build it. vi Preface Mine is based on plausibility which covers with precision a wider field than probability and makes the formalization of analogy and generalization possible. As Laplace said: "Even in the mathematical sciences, our principal instru ments to discover the truth are induction and analogy. " The examples of application I have chosen are not des cribed in detail.