5 / 06
Image of birds flying. Image of birds flying.

#339 God’s Necessity and the Causal Principle on a B-Theory of Time

October 14, 2013

Dear Dr. Craig,

In Question #329 you write '...it makes no sense to wonder, "if God exists, why does he exist?" That sort of puzzle is appropriate only for a being that exists contingently. But with respect to a necessary being, it's like wondering, "Why are all bachelors unmarried?"

I'm inclined to agree with you that if one adopts a tenseless or B-Theory of time, according to which all moments of time are equally real and temporal becoming is an illusion of human consciousness, then the kalam cosmological argument based upon the beginning of the universe is not the salient issue...'

I have questions about both points you make. In reponse to your first point on divine aseity it seems as though there is an epistemological dissimilarity with the bachelor, since in my mind I can see that a bachelor being unmarried is self-evidently the case, and thus I understand the necessity of a bachelor's marital status. With God, however, I cannot see his necessity in the same way. I don't doubt that He is in fact necessary, but since I cannot see His necessity I cannot truly understand it (even if I understand that it is the case that He is necessary). Anselm held that if one truly understands what it means to be God then one understands that He has to exist; unfortunately I do not yet understand what it means to be God and thus cannot see His necessity.

It seems as though necessary truths are explained by their meaning, so bachelors are necessarily unmarried by virtue of the meaning of bachelorhood. Similarly 2+2=4 is necessarily true by virtue of the values of 2 and 4. So it seems as though the concept of God entails His necessity in the same way. So my question is how does the concept of God entails his necessity in such a way?

An obvious response is that the aspect of God's nature which entails His necessity is His aseity, so God is necessary by virtue of the fact that He is by definition a necessary being. However this doesn't appear to be sufficient, since all bachelors being unmarried is also necessarily true by definition, but merely stating that bachelors are necessarily unmarried fails to explain the necessity. Rather bachelors are necessarily unmarried because bachelorhood contains unmarriedness. In the same way the concept of God must somehow contain His existence in order for His existence to be necessary.

In his ontological argument Anselm gives a model for understanding God's necessity based upon the concept of God as the greatest conceivable being, since for Anselm God's Greatness contains His existence. What model would you propose to explain God's existence being necessary?

In response to your doubts about the Kalam Cosmological Argument against a B-Theory of time couldn't one argue inductively that every entity with an edge in the earlier-than direction has a causal relationship with another entity at that edge (this seems nearly equivalent to the causal premise)? Since it is true for every entity we can test in this regard it seems to be plausible that for any entity we cannot test, if the entity has an earlier-than edge then it is very likely that it has a causal relationship with another entity at that edge. The universe has such an edge, therefore it is very likely that the universe has a causal relationship with another entity at that edge. Could such an argument work?

Thank you for all the work you do,

God Bless,


Flag of Australia. Australia

Photo of Dr. Craig.

Dr. craig’s response


Let’s take your two points one at a time, Rob. Your first point is really an objection to the ontological argument, not to God’s necessary existence. It is, in fact, Thomas Aquinas’s objection to Anselm’s ontological argument! Thomas differentiated between propositions which are self-evident in themselves and propositions which are self-evident to us. With respect to the proposition that God exists, Aquinas wrote,

I say that this proposition, ‘God exists,’ of itself is self-evident, for the predicate is the same as the subject; because God is His own existence. . . . Now because we do not know the essence of God, the proposition is not self-evident to us; but needs to be demonstrated by things that are more known to us, though less known in their nature--namely, by effects (Summa theologica pt. 1 quest. 2 art. 1).

By contrast, in the case of the bachelor, we can, as you say, “see that a bachelor being unmarried is self-evidently the case” because we understand that it belongs to the concept of a bachelor to be unmarried. Therefore, in Aquinas’ view, even though God exists is necessarily true, it isn’t evident to us that it is necessarily true due to our ignorance of God’s essence, and so the ontological argument fails.

Now whether or not you think this is a good objection to the ontological argument (I don’t), it’s irrelevant, as Thomas realized, to God’s aseity and necessary existence. God’s existing necessarily doesn’t depend on its being self-evident to us. Just as a complex mathematical equation may be necessarily true, even though we can’t even understand it, so God exists may be necessarily true even though it’s not obvious to us. So the failure of the ontological argument does nothing to undermine God’s necessary existence.

Don’t think that all necessary truths are true just by definition. Examples of necessary truths which are not definitional include: Everything that is colored is extended; Nothing is simultaneously red all over and green all over; Gold has the atomic number 78; My shoes could not have been made of steel; No event precedes itself; Everything that comes into being has a cause; and so on. Similarly, God exists need not be thought to be true by definition.

I agree with Anselm that God, as the greatest conceivable being, must have necessary existence as an essential property. For necessary existence is a great-making property. That entails that in every possible world in which God exists, He has the property of necessary existence.

That brings us back to the ontological argument. For if God has necessary existence in any possible world, then He exists in every world, including the actual world. So if God’s existence is even possible, He must actually exist. The real issue for the ontological argument is not whether we can see that God exists necessarily, as Aquinas thought, but whether we can see that God possibly exists.

As for your second question, although I am wedded to the A-theory of time, according to which temporal becoming is an objective feature of reality and the past, present, and future are not on an ontological par, still I’m glad that B-theorists want to defend the causal premiss of the kalam cosmological argument. One B-theorist said to me, “If a horse starts to exists at some time t, of course the B-theorist would say that there has to be a cause earlier than t that explains why there is (tenselessly) a horse at t!” That seems eminently sensible to me. Your inductive argument would supply some justification for holding to the causal principle, though it falls far below the metaphysical grounds which the A-theorist can offer in justification of the principle, namely, that something cannot come into being from nothing.

- William Lane Craig