Lives and Opinions of Eminent Philosophers

​Leucippus was a native of Elea, but according to some, of Abdera, and according to others, of Miletus. He was a pupil of Zeno. His doctrines were that the all is infinite and changes into one another, and that the universe is void and full [of bodies]. He also held that worlds are formed when bodies fall into the void and become entangled with one another; and that from their motion as they increase in size arises the nature of the heavenly bodies. Further, that the sun moves in a larger orbit around the moon; that the earth rides along whirling around the center; and that its shape is like a drum. He was also the first to posit atoms as first principles. In sum, these are his views, but in detail they are as follows.

​The all, as has been said before, he declares to be infinite; of this, one part is full and the other void, which he also calls elements. From these, infinite worlds arise and dissolve back into them. And the worlds arise in this way: many bodies of every shape are borne off by severance from the infinite into a great void, which, having gathered together, produce a single vortex, in accordance with which they strike against one another and, circling in all directions, like are sorted out apart toward like. But when, owing to their vast quantity, they can no longer revolve while keeping their balance, the fine particles pass out into the outer void, as if sifted through; while the rest remain together and, becoming entangled, rush along with one another and form a primary spherical system.

​And this system separates off like a membrane, enclosing within itself all kinds of bodies; as these whirl around in accordance with the counter-resistance of the center, the surrounding membrane becomes thin, since adjacent bodies continually flow together upon touching the vortex. And in this way the earth came to be, the bodies that were borne to the center remaining together. Moreover, the enclosing membrane-like structure itself increases in size through the accretion of bodies from without; and, being borne along in the vortex, it acquires and absorbs whatever it touches. Certain of these bodies, becoming entangled, form a system which at first is moist and muddy, but when dried and carried around with the whirl of the whole, subsequently catches fire and produces the substance of the stars.

​The orbit of the sun is the outermost, while that of the moon is closest to the earth, and the orbits of the others are between these. All the stars are ignited on account of the velocity of their movement, but the sun is also set ablaze by the stars, whereas the moon partakes of but little fire. Eclipses of the sun and the moon occur [… and the obliquity of the Zodiac arose] because the earth is tilted toward the south; while the northern regions are perpetually snow-bound, extremely cold, and frozen. The sun is eclipsed rarely, but the moon frequently, because their orbits are unequal. And just as there are generations of worlds, so also there are growths, decays, and destructions, in accordance with a certain necessity, though what sort of necessity this is, he does not make clear.