Leibniz et la raison paresseuse

The argument of the “lazy reason” is commonly regarded as an argument for fatalism, namely for the thesis that our actions have no influence on the course of natural events. Although it is mostly considered as a bad reasoning, it is not immediately evident why it does not work. One of the best criticism against it involves the contemporary semantics of possible words. Now, in his Theodicy Leibniz both charges the sophism of the lazy reason (or Fatum Mahometanum), and introduces its mature conception of possible worlds. So, I will show the affinities between Leibniz ideas and the more recent accounts of the argument. Moreover, I will argue that Leibniz’s refusal of the lazy reason is due not only to logical and metaphysical notions, but also to a further aim. It consists in replacing standard fatalism with his personal version of fatalism, a different thesis which is grounded on Leibniz’s peculiar conception of the relation between subject (the substance that spontaneously acts), and nature (conceived as the world within the subject acts, together with its rules).