The fourth argument[303] was based upon the impossibility of action between an infinite body and a second body whether finite or infinite. An infinite cannot act upon a finite because the action would necessarily be timeless. Were it in time we could then find a finite body which in the same time would produce the same effect; but there can be no such equality between the finite and the infinite. Similarly action between two infinites would occur in infinite time; in other words, would not take place at all. The conclusion is that neither fire nor earth nor any of the elements can be infinite in quantity. Bruno suggests, in the first place,[304] that a change may be produced timelessly; thus if a body in a large circle cover a certain space in the _minimum_ of time, a body in a smaller circle will cover a less space in _no_ time, for nothing can be smaller than the minimum.[305] In the second place, no action of the whole or effect upon the whole exists, it is only the finite bodies within it, each with its finite force, that act upon one another. Even if two infinite bodies, over against one another, were supposed, their action would not be of one whole upon another, but of the parts on the contiguous parts.[306] Force is exerted by bodies not _intensively_ but _extensively_, because as, where one part of a body is, there another is not, so at the point where one part of the body acts another does not.[307] [Sidenote: 5. Proportion of parts to whole in the infinite.] A difficulty, not unknown to recent philosophy, occurred as to the relation of infinites to one another. Whatever is an element of the infinite must be infinite also; hence both earths and suns are infinite in number. But the infinity of the former, said Bruno, is not greater than that of the latter; nor, where all are inhabited, are the inhabitants in greater proportion to the infinite than the stars themselves.[308] Each sun is surrounded by several earths or planets, but the one class is not greater in respect of its infinite than the other. A single sun, earth, constellation, is not really a part of the infinite nor a part in it, for it can bear no proportion to it. A thousand infinities are not more than two or three, and even _one_ is not comprehensible by finite numbers. In the innumerable and the immeasurable there is no place for more or less, few or many, nor for any distinctions of number or measure.[309] The matter of the stars is immeasurable, and no less immeasurable is that of the fiery type or suns than of the aqueous type or earths. Nor does the fact that these infinities are not given to sense disprove their existence, as Aristotle had maintained. To imagine there is nothing beyond the sphere which limits our range of sight, is to be like Bruno as a child, when he believed there was nothing beyond Mount Vesuvius because there _was_ nothing to strike his senses.[310] Though each class be infinite, we have seen that the infinite does not act infinitely, that is