Religious considerations also led Valla to find fault with another fundamental tenet of Aristotelian scholastic thought: the Tree of Porphyry (Repastinatio, 1:46–50; 2:389–391; DD 1:82–88). Valla has several problems with the Tree. First of all, it puts substance, rather than thing, on top. For Valla, however, pure substance does not exist, since a thing is always already a qualified substance. He also thinks that there is no place for a human being in the Tree of Porphyry. Since the Tree divide