the aggregate, and the existence of the aggregate entails that none of its components is absent. Thus, whatever entails the existence of the aggregate entails the existence of each of its components, even if that which entails it is not an efficient cause. How much more so, then, if it is an efficient cause? It is therefore clear that an efficient cause of the aggregate must be a cause of each of its components.

If someone were to suppose that one constituent of the aggregate is the cause of all the remaining components, while those components are the cause of the aggregate; or that it is the cause of the aggregate, while the aggregate is the cause of the individual constituents—so that this one constituent would be the cause of the cause—we would reply:

This does not undermine the argument, for a cause is a cause. Just as an individual constituent cannot be the cause of its own cause, it is all the more impossible for it to be its own cause. Thus, if one component were the cause of the aggregate, and the aggregate the cause of each component, or vice versa, that component would necessarily be the cause of its own cause and the cause of its own causes—namely, the causes preceding that component, which were assumed to have no end.

This is plain: no one can conceive of it without knowing its impossibility as a self-evident matter. Anyone who disputes it does so either because he has not conceived of it or out of obstinacy. In that case, it suffices to say:

“This is self-evidently known. The objection raised against it is of the same kind as the sophists’ objections and therefore merits no answer.”