Descartes, in 1644, advances the notion that the activities of organisms (including humans) occur as a reaction to external stimuli.
The World, originally titled Le Monde and also called Treatise on the Light, written by Descartes between 1629 and 1633, contains a relatively complete version of his philosophy, from method, to metaphysics, to physics and biology.
A follower of the mechanical philosophy, a form of natural philosophy popular in the seventeenth century, Descartes thinks everything physical in the universe to be made of tiny "corpuscles" of matter.
Corpuscularianism is a viewpoint closely related to atomism.
The main difference is that Descartes maintains that there can be no vacuum, and all matter is constantly swirling to prevent a void as corpuscles move through other matter.
The World presents a corpuscularian cosmology in which swirling vortices explain, among other phenomena, the creation of our solar system and the circular motion of planets around the Sun.
Because the work endorses the Copernican view of the moving earth, Descartes had cautiously delayed its release when he heard of the condemnation of Galileo’s Copernicanism by the Catholic Church in Rome and the subsequent burning of the related works.
Descartes had discussed his work on the book, and his decision not to release it, in correspondence with another philosopher, Marin Mersenne.
Some material from The World is revised for publication as Principia philosophiae or Principles of Philosophy (1644), a Latin textbook at first intended by Descartes to replace the Aristotelian textbooks used in universities.
In the Principles, the Copernican tone is softened slightly with a relativist frame of reference.
