Category Archives: Thomism

The Problem of a Necessary Being Causing a Contingent World

There seems to be the following contradiction (or, at least, puzzle) in saying that a necessary being explains the contingent world. Consider.

It is normally assumed that a necessary being (NB) can explain the contingent world (CW) by some causal action taking place in the NB. However, this seems viciously circular. For the causal action that gives rise to the CW cannot be in the CW, since it accounts for it. But if the action is in the NB, then it is an item either itself necessary, or contingent. If contingent, then we must account for it by some further contingency, etc, until we get to some causal action that is necessary. But then, this action must necessarily be in the NB. In which case, the action which gives rise to the CW is necessary. For given the NB, it’s causal action will necessarily be present in it, and the CW will necessarily exist.

Thus, if a NB causally accounts for a CW, the CW is likewise necessary.

Another way to put the problem is like this. What explains the CW? Such a cause is either contingent, or necessary. If necessary, then, it must necessarily be what it is and cannot be otherwise. For any contingency in the cause must be explained by some prior necessity. But then, when we reach this necessary cause, its action must be necessary: it must necessarily do what it does. But what it does is cause the CW.  But then, the CW is no longer contingent, but necessary.

Now, this appears to only be a contradiction on Thomistic metaphysics. For if God is temporal or everlasting it seems a NB could cause a CW by a spontaneous act of freedom. This may be mysterious or even incomprehensible – but it also may avoid the contradiction above.

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A Self-Contradiction in Thomistic Metaphysics

Here is the end of a recent exchange I had with a Thomist.

Fr. Joe,

Thanks for your reply. I agree that God must be essentially incomprehensible to us. What I am wondering is if Aristotelean metaphysics allows us to retain this mystery or if it entails contradictions. I suspect the latter is the case, given the difficulty of explaining God’s knowledge of the world.

The contradiction – which I’ve not seen even possibly explained – is precisely this. God knows truths which need not exist: for instance “the world exists.” This is an item in God contingently. God need not know “the world exists.” However, on Aristotelean metaphysics, nothing can cause itself. Thus the existence of any contingency must be referred to something outside itself to explain why it exists rather than not. There is nothing outside God, however. But then there is nothing to explain why God knows the world rather than not know it.

Further, nothing can be in act and in potency in the same respect. But God, if he may either know the world or not know it, is in potency towards this fact. But God knows the world. Therefore he knows it actually. But since he is in potency towards this fact, something outside him must explain why he knows it rather than not – something must actuate this potency. And again, since nothing can cause itself or act on itself in this metaphysics, something other than God must act on God to explain why he has knowledge of the world which he need not have.

Despite appeals to transcendence, I’ve not seen an answer to this problem that does not in fact entail a rejection of Aristotelean metaphysics.

For more on this line of thought, see below.