Corpuscular theory of light

In optics, the corpuscular theory of light, arguably set forward by Descartes states that light is made up of small discrete particles called "corpuscles" (little particles) which travel in a straight line with a finite velocity and possesses impetus. This was based on an alternate description of atomism of the time period.

In the early 17th century, natural philosophers were seeking new information to replace Aristotelianism that had been popular for centuries. Various European philosophers adopted what came to be known as mechanical philosophy sometime between around 1610 to 1650, which described the universe and its contents as a kind of large-scale mechanism, a philosophy that explained the universe is made with matter and motion. This mechanical philosophy was based on Epicureanism, and the work of Leucippus and his pupil Democritus and their atomism, in which everything in the universe, including a person's body, mind, soul and even thoughts, was made of atoms; very small particles of moving matter. During the early part of the 17th century, the atomistic portion of mechanical philosophy was largely developed by Gassendi, René Descartes and other atomists.

The core of Gassendi's philosophy is his atomist matter theory. In his great work, Syntagma Philosophicum, (“Philosophical Treatise”), published posthumously in 1658, Gassendi tried to explain aspects of matter and natural phenomena of the world in terms of atoms and the void. He took Epicurean atomism and modified it to be compatible with Christian theology, by suggesting several key changes to it:

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