What is it, then, said he, which you do not approve of in them, for I am very anxious to hear? In the first place, said I, he is utterly wrong in natural philosophy, which is his principal boast. He only makes some additions to the doctrine of Democritus, altering very little, and that in such a way that he seems to me to make those points worse which he endeavours to correct. He believes that atoms, as he calls them, that is to say bodies which by reason of their solidity are indivisible, are borne about in an interminable vacuum, destitute of any highest, or lowest, or middle, or furthest, or nearest boundary, in such a manner that by their concourse they cohere together; by which cohesion everything which exists and which is seen is formed. And he thinks that motion of atoms should be understood never to have had a beginning, but to have subsisted from all eternity.
But in those matters in which Epicurus follows Democritus, he is usually not very wrong. Although there are manyassertions of each with which I disagree, and especially with this—that as in the nature of things there are two points which must be inquired into,—one, what the material out of which everything is made, is; the other, what the power is which makes everything,—they discussed only the material, and omitted all consideration of the efficient power and cause. However, that is a fault common to both of them; but these blunders which I am going to mention are Epicurus's own.
For he thinks that those indivisible and solid bodies are borne downwards by their own weight in a straight line; and that this is the natural motion of all bodies. After this assertion, that shrewd man,—as it occurred to him, that if everything were borne downwards in a straight line, as I have just said, it would be quite impossible for one atom ever to touch another,—on this account he introduced another purely imaginary idea, and said that the atoms diverged a little from the straight line, which is the most impossible thing in the world. And he asserted that it is in this way that all those embraces, and conjunctions, and unions of the atoms with one another took place, by which the world was made, and all the parts of the world, and all that is in the world. And not only is all this idea perfectly childish, but it fails in effecting its object. For this very divergence is invented in a most capricious manner, (for he says that each atom diverges without any cause,) though nothing can be more discreditable to a natural philosopher than to say that anything takes place without a cause; and also, without any reason, he deprives atoms of that motion which is natural to every body of any weight (as he himself lays it down) which goes downwards from the upper regions; and at the same time he does not obtain the end for the sake of which he invented all these theories.
For if every atom diverges equally, still none will ever meet with one another so as to cohere; but if some diverge, and others are borne straight down by their natural inclination, in the first place this will be distributing provinces as it were among the atoms, and dividing them so that some are borne down straight, and others obliquely; and in the next place, this turbulent concourse of atoms, which is a blunder of Democritus also, will never be able to produce this beautifully ornamented world which we see around us. Even this,too, is inconsistent with the principles of natural philosophy, to believe that there is such a thing as a minimum; a thing which he indeed never would have fancied, if he had been willing to learn geometry from his friend Polyænus, instead of seeking to persuade him to give it up himself.
The sun appears to Democritus to be of vast size, as he is a man of learning and of a profound knowledge of geometry. Epicurus perhaps thinks that it is two feet across, for he thinks it of just that size which it appears to be, or perhaps a little larger or smaller. So what he changes he spoils; what he accepts comes entirely from Democritus,—the atoms, the vacuum, the appearances, which they call εἴδωλα, to the inroads of which it is owing not only that we see, but also that we think; and all that infiniteness, which they call ἀπειρία, is borrowed from Democritus; and also the innumerable worlds which are produced and perish every day. And although I cannot possibly agree myself with all those fancies, still I should not like to see Democritus, who is praised by every one else, blamed by this man who has followed him alone.