Book 2 · Section 66

(66) And in the country of the Cyclops, since the race of these men is a fabulous invention, there is no eatable fruit whatever produced except such as is raised from seed and cultivated by husbandmen, just as nothing is produced from that which does not exist; but we must not accuse Greece as being sterile and unproductive, for there is a great deal of deep and rich soil in it; and if the land of the barbarians is superior in fruitfulness, though it is superior in the food which it produces, it is inferior in the men who are nourished by the food, and for whose sake the food is produced.

For Greece is the only country which really produces man, that heavenly plant, that divine offshoot, producing that most accurately refined reason which is appropriated by and akin to knowledge; and the cause is this, it is the nature of the intellect to be rendered acute by the lightness of the air; (67) on which account Heraclitus said with great propriety, "Where the soil is dry, there the soul is most wise and most excellent;" and any one may conjecture this from the fact, that men who are sober and contented with a little are wise, and that those who are continually filling themselves with meat and drink are the least sensible, as if their reasoning faculties were drowned by the quantity which they swallow.