Quoted from 'An Introduction to Mathematics'
Edit: Alfred North Whitehead – (15 February 1861 – 30 December 1947) was an English mathematician and philosopher. He wrote on algebra, logic, foundations of mathematics, theology, philosophy of science, physics, metaphysics, and education. Whitehead supervised the doctoral dissertations of Bertrand Russell and Willard Van Orman Quine, thus influencing logic and virtually all of analytic philosophy. He co-authored the epochal Principia Mathematica with Russell and later the metaphysical treatise Process and Reality.