ABSTRACT
In his Essay North enters as a philosopher, and his tract itself is an illustration of a certain way of philosophising. His brother, John, had preferred Plato's way, 1 which also had been the preferred way of Descartes, who studied causes and the art of demonstration, seeking epistemological certainty in mathematics. Warning against mixing 'conjectures into the judgements we make about the truth of things', he had recommended the study of mathematics as a way to learn how to argue demonstratively rather than probably? Nevertheless, Descartes conceded that, where truth has yet to be established, we might make any hypothesis about the matters at hand, with the proviso that all the consequences of our assumption agree with our experience.3 And he had illustrated this way of philosophising in some of the essays published together with his Discours de Ia methode (1637).4
