so that all objects were, in themselves, fire, air, earth, and water, whatever might be the appearance which they presented to us. And, Thirdly, This process of mingling and separating was set in motion and governed by two principles, φιλία and νεῖκος; φιλία, friendship or love; and νεῖκος, enmity or hate.
3. After all my study of Empedocles and his expositors, I am unable to find in him anything better than a confused scheme of crude and fanciful physics. I shall therefore dismiss him, after having directed your attention to a certain dogma which has occupied an important place in the history of philosophy, and which, although current before the time of Empedocles, was first laid down by him in distinct and emphatic terms. The dogma to which I refer is the saying that like can be known only by like. "Similia similibus cognoscuntur;" that is to say, the thing which knows must be of a nature cognate or analogous to that which knows it, or, as Empedocles expresses it, "We perceive earth by means of earth (the earth, that is, of which we ourselves are made), we perceive water by means of water, and air by means of air, fire by means of fire, love by means of love, and strife by means of strife;" that is, it is by means of the earth, the water, the air, the fire, the love, and the strife of which our own nature is composed, that we are able to apprehend the earth, the water, the air, the fire, the love, and the strife that are external to us. A crude enough doctrine, as thus stated,
