Aristotle's theory of the limitation of space by the ultimate sphere of the heavens was open to objections, many of which were raised in the early schools. The "subtle Averroes" had endeavoured to avoid some of these by the doctrine that beyond this outer sphere is the divine being, the eternal self-sufficient Mind.[292] "But how," asks Bruno, "can body be bounded by that which is not body? The divine nature is no less nor in any other manner _within_ the whole than _without_; it is neither place nor in place."[293] Space therefore is always bounded by space, body by body, that is, each is infinite in extent. Were divinity that which bounds space, it would itself be space under another name.[294] Aristotle's theory implied that the universe as a whole was not in any place or space. The "place" of each body, he had said, is the containing surface of the sphere above it; the outermost sphere, therefore, as there is no other beyond it, is itself uncontained and without place. The theory implied also the identity of body and space, and was the ground of Aristotle's rejection of the vacuum in nature. For a truer conception of Space, Bruno turned to an earlier commentator (or group of commentators--"Philoponus") on Aristotle, who defined it as "a continuous physical quantity in three dimensions, in which the magnitude of bodies is contained, in nature before and apart from all bodies, receiving all indifferently, beyond all conditions of action and passion, not mixing with things, impenetrable, without form or place."[295] It is called _physical_, because it can not be separated from the existence of natural things. It is itself not contained, because it equals with its dimensions those of body as the transparency of a crystal has the same dimensions with the crystal itself. Neither body nor space can be thought of the one apart from the other.[296] Granted the infinity of space, that of matter necessarily follows by an inverse of the principle of sufficient reason:--for there is no reason, according to Bruno, why this small part alone of space, where our earth is, should be filled; the eternal operation is not distinct from the eternal power, nor could it be the will of God to cramp nature, which is the hand of the all-powerful, his force, act, reason, word, voice, order and will.[297] "There is one matter, one power, one space, one efficient cause, God and Nature, everywhere equally, and everywhere powerful.--We insult the infinite cause when we say that it may be the cause of a finite effect; to a finite effect it can have neither the name nor the relation of an efficient."[298]