Abstract

For Aquinas the vegetative powers of the soul (viz. nutrition, growth, and reproduction) are properties of living organisms: that is, they are characteristics of living organisms which, while not being essential characteristics, can nevertheless be predicated necessarily and convertibly of living organisms. Furthermore, they are active powers in the sense that they are capacities to perform certain actions which can have effects. But such and interpretation of Aquinas leads to the conceptual difficulty of allowing for the possibility of non-active living organisms (i.e., organisms which do nothing). This difficulty can be avoided if we consider at least one of the vegetative powers as being a capacity which is of necessity always exercised, and this not because of what it is, but because of what it is related to. Thus, on this interpretation, all living organisms perform at least one action by consequence of their necessary relation to an end.