Cartesianism is the philosophical and scientific system of René Descartes and its subsequent development by other seventeenth century thinkers, most notably François Poullain de la Barre, Nicolas Malebranche and Baruch Spinoza. Descartes is often regarded as the first thinker to emphasize the use of reason to develop the natural sciences. For him, philosophy was a thinking system that embodied all knowledge.
Aristotle and St. Augustine's work influenced Descartes's cogito argument.Additionally, there is similarity between Descartes's work and that of Scottish philosopher George Campbell's 1776 publication, titled Philosophy of Rhetoric. In his Meditations on First Philosophy he writes, "[b]ut what then am I? A thing which thinks. What is a thing which thinks? It is a thing which doubts, understands, [conceives], affirms, denies, wills, refuses, which also imagines and feels."