Aristotle defines substance as what is neither said of many nor existent by its presence in something.
Thesis: without substance, nothing either loves or acts.
If there is no substance, then all that is is said of many. But then all that is loved is said of many, and so we might replace anything loved with something else. But this is the same as not to love it at all.
If there were no substance, then there would be no love only use. But use is unintelligible except as love of self, or benefit to self. Use makes no sense as benefit to another. And so whether we act for a self or for another, there must be what is neither said of many nor present in another.
But all actions are either for self or other, for preservation or as the result of something preserving itself. (really? even when nature moves in cycles? Here too, the cycle preserves itself.)