In the debate between IT specialists, two major language families are opposed: the imperatives, the archetysis of which is BASIC, and the reccursives, in the LISP. Rather than languages, these are forms of thought: there are those who need to know how to calculate a certain number, and those for whom it is sufficient to define it precisely. The author would like to show how this is the resurgence in computer science of a debate that has agitated the mathematical class for almost a century.