 (iv) The “distinctive function” argument is inherently unsatisfying in ways that could hardly have failed to be apparent to so able a philosopher as Aquinas. (a) In Aquinas’ rendering, it depends on the postulate that “nature does nothing in vain”, which in turn depends, according to Aquinas, on the premise that nature is the product of divine creative rationality, a premise which Aquinas himself argues is, though provable, by no means self-evident. (b) It seems arbitrary to assume that, if there is an appropriate function or operatio of human beings, it must be peculiar to them. For peculiarity or distinctiveness has no inherent relationship to practical fittingness, and in fact Aquinas elsewhere denies that rationality is peculiar to human beings since he holds that there are other intelligent creatures (the angels, understood to be created minds unmixed with matter, occupying what would otherwise be a surprising gap in the hierarchy of beings which ascends from the most material and inactive kinds through the vegetative kinds, the animal kinds, and the rational animal humankind, to the one utterly active and intelligent, non-dependent and uncreated divine being).