Note 22 — Chapter XVII · THE EPICUREAN VIEWS ON NATURE.

Not only must atoms, like all other bodies, have shape, but there must exist among them indefinitely many varieties of shape, or it would be impossible to account for the innumerable differences of things. There cannot, however, be really an infinite number of shapes, as Democritus maintained, in any limited body—this is intelligible of itself—nor yet in the whole universe,22 since an unlimited number would make the arrangement of the world impossible, everything in the world being circumscribed by certain containing limits.23 Again, atoms must be different in point of size; for all materials cannot be divided into particles of equal size. Yet even to this difference there must be some limitation. An atom must neither be so large as to become an object of sense, nor can it, after what has been said, be infinitely small.24 From difference in point of size the difference of atoms in point of weight follows.25 In point of number atoms must be innumerable, and in the same way empty space must be unbounded also. For since everything bounded must be bounded by something, it is impossible to imagine any bounds of the universe beyond which nothing exists, and hence there can be no bounds at all. The absence of bounds must, apply to the mass of atoms quite as much as to empty space. If an infinite number of atoms would not find room in a limited space, conversely a limited number of atoms would be lost in empty space, and never able to form a world.26 In all these views Epicurus closely follows Democritus, no doubt agreeing with him also in explaining the qualities of things by the composition of their atoms.27