THOMAS AQUINAS ON NECESSARY TRUTHS
ABOUT CONTINGENT BEINGS
Gloria Ruth Frost
The aim of this dissertation is to give an account of Aquinas’s thinking on the
ontological grounds of necessary propositions about creatures. The kind of necessary
propositions that this dissertation concerns are essential propositions, such as Man is
an animal or Dogs are sentient. Throughout his works Aquinas affirms that every
truth asserted by the human intellect is adequated to or conforms to some res.
Accordingly, it seems that if necessary propositions are true at all times, then there
must be some res that exists at all times to which these necessary propositions
conform. Since both creatures and their essences are contingently existing beings that
come to be and perish in time, many have concluded that the creatures themselves or
their essences cannot be the res to which necessary propositions about creatures
conform. It seems for example, that the proposition Dodo birds cannot fly cannot be
grounded by dodo birds or their essences since both dodo birds and their essences
ceased to exist almost four hundred years ago and still this proposition remains true.