Always remember the saying of Heraclitus, that the death of earth is to become water, and the death of water is to become air, and the death of air is to become fire, and reversely. And think too of him who forgets whither the way leads, and that men quarrel with that with which they are most constantly in communion, the reason which governs the universe; and the things which daily meet with seem to them strange: and consider that we ought not to act and speak as if we were asleep, for even in sleep we seem to act and speak; and that we ought not, like children who learn from their parents, simply to act and speak as we have been taught.
All things which participate in anything which is common to them all move towards that which is of the same kind with themselves. Everything which is earthy turns towards the earth, everything which is liquid flows together, and everything which is of an aerial kind does the same, so that they require something to keep them asunder, and the application of force. Fire indeed moves upwards on account of the elemental fire, but it is so ready to be kindled together with all the fire which is here, that even every substance which is somewhat dry, is easily ignited, because there is less mingled with it of that which is a hindrance to ignition. Accordingly then everything also which participates in the common intelligent nature moves in like manner towards that which is of the same kind with itself, or moves even more.