has a sight sufficiently piercing to penetrate into heaven, and dive into the earth. We do not understand our own bodies: we do not know what is the situation of their different parts, or what power each part has: therefore, the physicians themselves, whose business it was to understand these things, have opened bodies in order to lay those parts open to view. And yet empirics say that they are not the better known for that; because it is possible that, by being laid open and uncovered, they may be changed. But is it possible for us, in the same manner, to anatomize, and open, and dissect the natures of things, so as to see whether the earth is firmly fixed on its foundations and sticks firm on its roots, if I may so say, or whether it hangs in the middle of a vacuum? Xenophanes says that the moon is inhabited, and that it is a country of many cities and mountains. These assertions seem strange, but the man who has made them could not take his oath that such is the case; nor could I take mine that it is not the case. You also say that, opposite to us, on the contrary side of the earth, there are people who stand with their feet opposite to our feet, and you call them Antipodes. Why are you more angry with me, who do not despise these theories, than with those who, when they hear them, think that you are beside yourselves?
Hiretas of Syracuse, as Theophrastus tells us, thinks that the sun, and moon, and stars, and all the heavenly bodies, in short, stand still; and that nothing in the world moves except the earth; and, as that turns and revolves on its own axis with the greatest rapidity, he thinks that everything is made to appear by it as if it were the heaven which is moved while the earth stands still. And, indeed, some people think that Plato, in the Timæus, asserts this, only rather obscurely. What is your opinion, Epicurus? Speak. Do you think that the sun is so small?—Do I? Do you yourselves think it so large? But all of you are ridiculed by him, and you in your turn mock him. Socrates, then, is free from this ridicule, and so is Ariston of Chios, who thinks that none of these matters can be known.
But I return to the mind and body. Is it sufficiently known by us what is the nature of the sinews and of the veins? Do we comprehend what the mind is?—where it is?—or, in short, whether it exists at all, or whether, as Dicæar-
