GIORDANO BRUNO. 253 the centre or towards the circumference, according to the point with respect to which they are considered. There is no difference of up and down, central and circumferential, with respect to the infinite universe. Moving bodies may be called light or heavy according as they are in motion to or from any particular point. But there is no absolute difference of " gravity " and " levity," as there is no absolute difference of central and circumferential positions. Bodies on the earth are said to have gravity with respect to the earth, because it is the system of which they are parts. The parts of the earth are related to the centre of the earth as the parts of an animal are related to the organic centre of that animal. If any part of the earth be removed to a great distance from the centre, it will not tend to return to its own place with a force proportional to its distance from that place (as the Peripatetics are obliged to maintain),. any more than a part of an animal, being removed, will tend to return to its place. When it is at an indefinite distance from the system of which it has formed part, a body has no tendency to return to that system ; for it is now neither light nor heavy with respect to it. Its motion will be determined by the general law that all bodies seek " the place of their pre- servation ". When a body is in "its own place," that is, the place of its preservation, it is again neither light nor heavy. Neither the material nor the spiritual substance of things seeks to preserve itself or fears to be destroyed, for substance is eternal. But all particular things, being subject to vicissi- tude, are moved by the desire to preserve themselves in their present state of being (il de-side rio di conservarsi ne.ll' esser prcsente). Contraries are found together in nature, and the desire of self-preservation expresses itself in general as love of that which is similar and hate of that which is dissimilar. But things may seek that which is unlike them in kind, instead of fleeing from it, if it tends to their preservation. The motion of the earth, which is called circular to dis- tinguish it from the rectilinear motion of the parts of the earth (though not one of the four motions of which the earth's total motion is composed is in a perfect circle), is determined by the need which the earth has of the light and heat of the sun. Not only is the earth the source of hie to the animals on its surface ; it is itself an animal. The sun and all planets and stars in the universe are also animals, which, hke the earth, though divine and perhaps not des- tined to perish, are yet generable and corruptible. They differ from the animals on their surface in that they have all
