Leucippus: Stoic

¹ Leucippus was a native of Velia or of Abdera or of Melos.

² He was a pupil of Zeno.

His principal doctrines were:

• all things were infinite and were interchanged with one another
• the universe was a vacuum full of bodies
• the worlds were produced by bodies falling into the vacuum, and becoming entangled with one another
• the nature of the stars originated in motion, according to their increase
• the sun is borne round in a greater circle around the moon
• the earth is carried on revolving round the centre
• its figure resembles a drum

He was the first to spoke of atoms as principles.

³ He says that one part is a plenum, and the other a vacuum.

The elements, and the worlds which are derived from them, are infinite, and are dissolved again into them.

The worlds are produced in this way: That many bodies, of various kinds and shapes, are borne by amputation from the infinite, into a vast vacuum.

They are then collected together, produce one vortex; according to which they, dashing against one another, and whirling about in every direction, are separated in such a way that like attaches itself to like.

But as they are all of equal weight, when by reason of their number they are no longer able to whirl about, the thin ones depart into the outer vacuum, as if they bounded through, and the others remain behind, and becoming entangled with one another, run together, and produce a sort of spherical shaped figure.

This subsists as a kind of membrane, containing within itself bodies of every kind; and as these are whirled about so as to revolve according to the resistance of the centre, the circumambient membrane becomes thin, since bodies are without ceasing, uniting according to the impulse given by the vortex; and in this way the earth is produced, since these bodies which have once been brought to the centre remain there.

On the other side, there is produced another enveloping membrane which increases incessantly by the accretion of exterior bodies.

As it is itself animated by a circular movement, drags with it, and adds to itself, everything it meets with.

Some of these bodies thus enveloped re-unite again and form compounds, which are at first moist and clayey, but soon becoming dry, and being drawn on in the universal movement of the circular vortex, they catch fire, and constitute the substance of the stars.

The orbit of the sun is the most distant one; that of the moon is the nearest to the earth; and between the two are the orbits of the other stars.

All the stars are set on fire by the rapidity of their own motion; and the sun is set on fire by the stars; the moon has only a slight quantity of fire; the sun and the moon are eclipsed in …[126] in consequence of the inclination of the earth towards the south.

In the north it always snows, and those districts are cold, and are often frozen.

The sun is eclipsed but seldom; but the moon frequently, because her orbits are unequal.

Leucippus also admits that the production of worlds, their increase, their diminution, and their destruction, depend on a certain necessity, the character of which he does not precisely explain.