EXCERPT In his Course on Logic, Kant says that [in defining logic,] to have any recourse to psychology would be ‘just as absurd as to derive morals from life’. ‘In logic,’ he says, the question is not about contingent but about necessary rules; not how we think, but how we ought to think. The rules of logic must thus be derived not from the contingent but from the necessary use of the understanding, which one finds in oneself apart from all psychology. And yet the introduction to his Course is unfortunately reminiscent of Arnauld’s Port-Royal Logic…