Introduction

In this section and in the following one our aim is only to give a slight flavor of the process that has led physicists to change completely their conception of reality by passing from classical mechanics to quantum mechanics. For a much more detailed presentation of this, we refer the reader to the very complete book [Mes], by A. Messiah. Interesting information can also be found in the book [Ro], by D. Robert (which is actually closer to our point of view), and in the classical book [LaLi], by L.D. Landau and E.M. Lifshitz. (Indeed, a large literature—in any language—exists on the foundations of quantum mechanics, and many more references can be found than we can give here.)