In his book The Coherence of Theism (Revised edition, hereafter: COT), Swinburne defends the claim that the sentence ‘God exists’ makes a coherent statement.

In Part II of COT, Swinburne defends the coherence of the concept of “a contingent God”, which is basically the traditional concept of God minus the attribute of ‘necessary being’. In Part III, Swinburne analyzes, clarifies, and defines the attribute ‘necessary being’, but he concludes that when this attribute is added back into the concept of ‘God’, it is no longer possible to prove in a direct way that the concept of ‘God’ is coherent, or that the claim ‘God exists’ makes a coherent statement.

The basic problem is that God is a person, but the concept of person allows for the logical possibility of gaining or losing knowledge, and gaining or losing power, and gaining or losing freedom. When it is asserted that ‘God is a necessary being’ the implication is that it is NOT possible for God to gain or lose power, to gain or lose knowledge, or to gain or lose freedom. So, God is a very odd sort of person, a person whose very existence has a necessary connection with his continuing to be omniscient, omnipotent, and perfectly free.

Swinburne’s analysis of the attribute ‘necessary being’ is complex and difficult. I’m not going to get into the gory details of his analyis. But even the general outlines of Swinburne’s understanding of this attribute are challenging to understand. I’m not entirely clear on what he means myself. But I’m going to attempt to understand and clarify some of the points Swinburne makes about ‘necessry being’. I will do this partly to help others understand this concept, but also partly to improve and clarify my own understanding (one of the best ways to get clearer on an idea is to try to explain it to other people).

Let’s start with a stripped-down version of Swinburne’s analysis of ‘a divine being’:

Definition 1:

X is A DIVINE BEING if and only if X is a person who is omnipotent, omniscient, and perfectly free.

Let’s note some important aspects of this definition. First, on this definition, something can be ‘a divine being’ for a brief period of time. This concept of ‘a divine being’ would be useful to Mormons, for example, because they believe that humans can evolve to become gods, and that God was once a limited and finite person. Given Definition 1, a person can be a limited and finite human being for several decades, and then become ‘a divine being’.

Another important thing to note about Definition 1 is that it allows for a person to be ‘a divine being’ even if that person has only existed for a few years or a few days. So long as a person is omnipotent NOW, and omniscient NOW, and perfectly free NOW, that person is correctly categorized as ‘a divine being’.

But, as Swinburne asserts, traditional theism makes a stronger claim than this. When theists assert that ‘God exists’ they have something more in mind than just that there is a person who has recently become omnipotent, omniscient, and perfectly free. They are asserting that there is a person who HAS ALWAYS had those divine attributes, and who ALWAYS WILL have those attributes.

We can formulate a revised definition that is more in keeping with traditional theism:

Definition 2:

X is A DIVINE BEING if and only if X is a person who has always been omnipotent, omniscient, and perfectly free, and who always will be omnipotent, omniscient, and perfectly free.

On this narrower definition, the being worshipped by Mormons would not count as ‘a divine being’ because there was a point in time in the past when (according to Mormon doctrine) this person was NOT omnipotent or NOT omniscient or NOT perfectly free. Such a being would be impressive now, but given its less impressive level of power, knowledge, and/or freedom in the past, would be something less than ‘a divine being’ if we go with Definition 2.

Also worth noting is that in order to have ALWAYS been omnipotent, a person must have ALWAYS been in existence. And in order to ALWAYS continue to be omnipotent, a person must ALWAYS continue to exist. Thus, any being that satisfies the conditions set by Definition 2 must be an eternal being, a person who has always existed in the past, and who will always continue to exist in the future.

According to Swinburne, the word ‘God’ is a proper name that should be understood in terms of a definite description that allows us to pick out or identify one particular person. The definite description is basically the same as the characterization of ‘a divine person’. So, this characterization is supposed to apply to one, and only one, person:

ANALYSIS of ‘God exists’:

GOD EXISTS is true if and only if (a) something is a divine being, and (b) nothing else is a divine being.

For this analysis of ‘God exists’ to represent traditional theism, the phrase ‘a divine being’ needs to be understood in terms of Definition 2, rather than Definition 1.

Suppose that we determine that a particular person has always existed and that this person has always been omnipotent, omniscient, and perfectly free. What about determining if this person will always continue to be omnipotent, omniscient, and perfectly free? This determination might be possible in a couple of ways.

First, the person in question might communicate to us that he/she would continue to be omnipotent, omniscient, and perfectly free for all eternity. If we were already convinced that this person was omnipotent, omniscient, and perfectly free, then we would have good reason to believe this person was telling us the truth. Being omniscient, the person would know whether it was true that he/she would continue to be omnipotent, omniscient, and perfectly free for all eternity, and being both omniscient and perfectly free, the person would (according to Swinburne’s argumentation) have to be perfectly good, and thus would not be a great deceiver, so we could trust this person to tell us the truth on this matter.

But even if we could not base this determination on ‘divine revelation’ (as described in the previous paragraph), we would have good inductive reason to believe that this person would continue to be omnipotent, omniscient, and perfectly free. Since we have already concluded that the person has always been omnipotent, omniscient, and perfectly free (stretching back in to eternity in the past), it makes great sense to infer that it is highly probable that this person will continue to be omnipotent, omniscient, and perfectly free for a long time to come, perhaps for all eternity.

Thus, it seems possible that we could determine that some person satisfied the conditions required to be ‘a divine person’. If we also became convinced, perhaps by a philosophical argument, that there could be AT MOST just one such person, then we could identify a particular person as being ‘God’ and conclude that ‘God exists’.

But even if we somehow were able to come to this incredible conclusion, there would still be a philosophical/conceptual problem that would mean that traditional theism had not yet been fully verified. According to Swinburne, traditional theists also maintain that God is ‘a necessary being’. One of the key implications of this is that it is NOT sufficient for a person to have always been omnipotent, omniscient, and perfectly free, and to always continue to be omnipotent, omniscient, and perfectly free into eternity in order for that person to be ‘God’. As ‘a necessary being’ it is NOT a matter of chance that this being has always been and will always be omnipotent, omniscient, and perfectly free. This person is such that it is not possible for him/her to be anything less than ‘a divine being’.

Take the eternal existence of this person, for example. A being could conceivably be lucky and simply avoid by chance numerous bad events and circumstances which would have put an end to the existence of that being. Continuing to exist for all eternity on the basis of chance or good luck is not enough to qualify a person as having the sort of eternality that God is supposed to have. The eternal existence of God cannot rest on chance or luck, it must somehow be necessary and unavoidable that God continues to exist for all eternity.

In other words, given the above analysis of ‘God exists’ and given that we understand ‘a divine person’ in terms of Definition 2, this still leaves open the possibility that we locate and identify a person who has IN FACT always existed, and who will IN FACT always continue to exist, but this person is not really and fully ‘God’ because his/her continued existence is a matter of chance or luck, and is not absolutely secure.

So, the definition needs to be revised again, in order to add the attribute of ‘necessary being’ into the concept of ‘a divine being’ and thus into the analysis of the sentence ‘God exists’.