Descartes is the father of modern philosophy, abstract, mathematical and scientific. In mathematics he is the father of algebraic geometry and laid the groundwork for the calculus of Newton and Leibnitz. In general Descartes rejected empirical knowledge for experimental confirmation, the throwing out several millennia of Aristotelian “science”. He even rejected the existence of his own body and the sensations provided by it. All knowledge must be proven and it set the stage for the enlightenment and rationalism. He developed an early form of the law of conservation of mechanical momentum. “Thus, God imparted various motions to the parts of matter when he first created them, and he now conserves all this matter in the same way, and by the same process by which he originally created it; and it follows from what we have said that this fact alone makes it most reasonable to think that God likewise always conserves the same quantity of motion in matter.” I hear echos of the conservation of mass espoused by Levoisier, the father of modern chemistry, Leibniz conservation of energy, Joule's mechanical equilalence of heat and even Einstein's conservation of matter and energy.