Ugh... math

Leibniz's mathematical investigations initially centered on the summation of infinite series. The concern with indivisibility and the infinitely small was linked in his mind to some fundamental, meta-physical truths about the nature of substance, matter, and mind. His intuition told him that the problem of how to make sense of the infinity of points on a line was an instance of the problem of how to make sense of the relation between indivisible, pointlike souls and the continuum of the material world. For roughly the same reason that no number of points could ever be strung together to make up a line, he believed that purely physical or material principles could not account for everything in the material world, and that therefore an incorporeal or "mental" principle- "substance"—was required to explain the unity and activity of phenomena. He called this complex of ideas "the labyrinth of the continuum." Pursuing these premises through one end of the labyrinth, he would discover calculus; off in the opposite direction, he would envision a world comprised of nothing but an infinite number of pointlike, immortal souls. All of Leibniz's mathematical achievements in later life, and much of his metaphysics as well, had their origin in the ideas conceived in Paris before he turned thirty.