While this controversy developed between rival French philosophers, two of the leading English scientists of the seventeenth century took up the particles-versus-waves battle. Pierre Gassendi, a contemporary of Descartes, challenged this theory, asserting that light was made up of discrete particles. Much like Aristotle, he believed that light was a disturbance that traveled through the plenum, like a wave that travels through water. The French philosopher and mathematician Rene Descartes believed that an invisible substance, which he called the plenum, permeated the universe.

In the seventeenth century, two distinct models emerged from France to explain the phenomenon of light. Alhazen's theory was contrary to earlier theories proposing that we could see because our eyes emitted light to illuminate the objects around us. In the tenth century CE, the Middle Eastern mathematician Alhazen developed a theory that all objects radiate their own light. Centuries later, Lucretius, who, like Democritus before him, believed that matter consisted of indivisible 'atoms,' thought that light must be a particle given off by the sun. Aristotle believed that light was some kind of disturbance in the air, one of his four 'elements' that composed matter. The earliest documented theories of light came from the ancient Greeks. Whether to a prehistoric child warming herself by the light of a fire in a cave, or to a modern child afraid to go to sleep without the lights on, light has always given comfort and reassurance. For as long as the human imagination has sought to make meaning of the world, we have recognized light as essential to our existence.

Particle model of light phenomena