a part, whereas this is not true of the whole. Each individual comes into existence after not existing—that is, it has a beginning—whereas the whole, according to them, has no beginning.

It thus becomes clear that whoever admits a beginningless succession of originated things—namely, the changing forms of the four elements—cannot deny an infinite succession of causes. It follows that this difficulty leaves them no way to establish the First Principle, and their position amounts to sheer arbitrary assertion.’

If it is objected:

‘The revolutions do not exist at present, nor do the forms of the elements; only a single form among them actually exists. What does not exist cannot be described as finite or infinite unless its existence is posited in the imagination. Such imaginary suppositions present no difficulty: if some of the things thus posited are causes of others, a person can suppose this in his imagination. But the discussion concerns what exists in external reality, not in the mind. Only the souls of the dead remain. Yet it has been held