Applying the Foundational Method

The foundational or mathematical method reduces to the method of hypothetical models when applied. René Descartes brilliantly used it to derive a new sine law of refraction. He suggested that light is pressure but conforms to the laws of motion. A model of colors gives us an analysis of the rainbow that was widely and rightly admired in his time. He derived many well-known color phenomena from his theory that colored light is a state of sunlight. A color is like a twist on a moving ball, which the retina feels when the light (ball) presses on it. He used multiple models to illustrate his many optical claims, comparing light to a rigid walking stick, to wine pressing down in a vat, and to a tennis ball moving on a path impeded at a surface.