Leibniz was the last major figure of seventeenth-century rationalism who contributed heavily to other fields such as metaphysics, epistemology, logic, mathematics, physics, jurisprudence, and the philosophy of religion; he is also considered to be one of the last “universal geniuses”. He did not develop his system, however, independently of these advances. Leibniz rejected Cartesian dualism and denied the existence of a material world. In Leibniz’s view there are infinitely many simple substances, which he called “monads” (which he derived directly from Proclus).