10.1 Can There Be Created Yet Necessary Things? (SCG 2,30)
10.1 Can There Be Created Yet Necessary Things? (SCG 2,30)
According to Aquinas something is “simply and absolutely necessary” if it is not able to be or not to be. One might think he regards all creatures as able to be or not to be and that he should, therefore, assume that no creature exists of absolute necessity, and Aquinas is clear that no creature has to exist by nature (since its nature and existence can be distinguished from each other, and since its existence must be caused by God). However, Aquinas does think that some things created by God have a necessity that does not conflict with the fact that what they are by nature does not entail that they exist as God does: as eternal, simple, and underived.
Philosophers have often spoken about contingency and necessity by appealing to certain propositions and then applying what they have said when it comes to things that exist. Consider the proposition “No triangles are square.” That seems to be logically necessary. But also consider the proposition “Australia exists.” That you might think is not true of logical necessity. Indeed, if you thought that it was true of logical necessity, then you would suppose that Australia has always existed and could not possibly cease to exist. So let us say that “Australia exists” is not true of logical necessity as is “No triangles are square.” In that case, Australia would seem to be something contingent, something that does not exist of logical necessity. So, it has consequently been said, there are things of two kinds: things that are logically necessary (the existence of which it would be contradictory to deny), and things that are contingent (the existence of which it would not be contradictory to deny). Yet, though Aquinas is perfectly aware of the distinction between propositions that are logically necessary and propositions that are not, he thinks that there are creatures of God that are necessary while other ones are contingent.
That is because Aquinas takes necessary creatures to be ones that (1) do not arise by a process of generation, and (2) cannot be annihilated by what exists in the material world. He says:
Some things are so created by God that there is in their nature a potentiality to non-being; and this results from the fact that the matter present in them is in potentiality with respect to another form. On the other hand, neither immaterial things, nor things whose matter is not receptive of another form, have potentiality to non-being, so that their being is absolutely and simply necessary.2
Aquinas’s distinction between creatures that are necessary and creatures that are contingent is not the distinction between what is logically necessary and logically contingent. It flags a difference between actually existing things created by God, and Aquinas, therefore, does not think that there being necessary created things conflicts with the view that all creatures depend for their existence on God’s will.
You might think that if creatures come to be from nothing, then none of them can be necessary. However, though Aquinas accepts that all creatures derive from God, and though he is certain that God might never have created since (1) God does not need creatures and since (2) no agent can compel God to do anything, he does not think it therefore follows that there can be no created necessary things. Such things, Aquinas holds, are just beings of a certain kind, beings that could be and that, therefore, can be created by God. “To be simply necessary,” says Aquinas, “is not incompatible with the notion of created being; for nothing prevents a thing being necessary whose necessity nevertheless has a cause, as in the case of the conclusions of demonstrations. Hence, nothing prevents certain things being produced by God in such fashion that they exist in a simply necessary way; indeed, this is a proof of God’s perfection.”3