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.