A key figure in the scientific revolution of the seventeenth century, René Descartes (1596–1650) was a French-born philosopher, mathematician and scientist whose work had a seminal influence on Newton in his early years at Cambridge. Descartes developed a set of fundamental principles or truths:

All Philosophy is like a tree, of which Metaphysics is the root, Physics the trunk, and all the other sciences the branches that grow out of this trunk, which are reduced to three principals, namely, Medicine, Mechanics, and Ethics. By the science of Morals, I understand the highest and most perfect which, presupposing an entire knowledge of the other sciences, is the last degree of wisdom.

This Cartesian approach to science was considered unsophisticated in the eighteenth century and was identified with Europe’s absolute monarchies and the reactionary nature of the Catholic Church. Descartes’ concept that scientific knowledge could be derived a priori by deductive reasoning or ideas that are innate to the human mind stood in contrast to Newtonian science which held that scientific theories should be based on rational observation, and measured and tested experience, an approach that extended beyond science with resonance in both politics and theology.