Although there is an extensive discussion of the meaning of the claim ‘God is a necessary being’ by Richard Swinburne in his bookThe Coherence of Theism (revised edition, hereafter: COT), the main passages that I’m interested in understanding are found in a shorter and more popular book: Is There a God? (hereafter: ITAG), also by Swinburne.

In COT, Swinburne specifies two implications of the claim that ‘God is a necessary being’:

However, most theists, and certainly most theologians, have put forward two further claims [in addition to the usual claims about God’s divine attributes: omniscience, omnipotence, perfect goodness, etc.] which they have made central to their theism…. The first such claim is that God does not just happen to exist. It is not a matter of fortunate accident that there is a God; he exists necessarily. The other is that God is necessarily the kind of being which he is; God does not just happen to have the properties which he does. It is not by chance that he is omnipotent or omniscient. Being omnipotent is part of God’s nature.

(COT, p.241-242)

This gives us a general understanding and a feel for the meaning of the claim that ‘God is a necessary being’.

In ITAG, Swinburne provides further discussion of what this means, a discussion that is simpler and easier to follow than what he says in COT. First, he briefly explains the idea that God’s divine attributes are possessed necessarily:

But theism does not claim merely that the person who is God has these properties of being everlastingly omnipotent, omniscient, and perfectly free. It claims that God has these properties necessarily–these are essential properties of God.

(ITAG, p.18)

So, to say that, for example, ‘God has the property of being everlastingly omnipotent necessarily‘ means that ‘Being everlastingly omnipotent is an essential property of the person who is God’.

But this is only helpful if we understand what it means for a property to be an ‘essential property’ of a thing or a person. Here is his initial clarification:

Every object has some essential properties and some accidental (i.e. non-essential) properties. The essential properties of an object are those which it cannot lose without ceasing to exist.

(ITAG, p.18)

Swinburne gives two examples to illustrate this concept. The first example is about a physical object:

One of the essential properties of my desk, for example, is that it occupies space. It could not cease to occupy space (become disembodied) and yet continue to exist. Byt contrast, one of its accidental properties is being brown. It could still exist if I painted it red so that it was no longer brown.

(ITAG, p.18)

He gives a second example about a person (himself):

Persons are essentially objects with the potential to have (intentional) powers, purposes, and beliefs. I may be temporarily paralysed and unconscious and so have temporarily lost the power to think or move my limbs. But, if I lose the potential to have these powers (if I lose them beyond the power of medical or other help to restore them), then I cease to exist. On the other hand, my powers can grow or diminish, and my beliefs can change (I can forget things I once knew, and aquire new areas of knowledge), while the same I continues to exist through all the change.

(ITAG, p.18-19)

If Swinburne loses the potential to have the power of thinking, then Swinburne will cease to exist (even if his body continues to exist). So the property of ‘having the potential to have power of thinking’ is an essential property of Swinburne. But if Swinburne forgets the proof for Bayes Theorem, he can continue to exist. So, knowing the proof for Bayes Theorem is only an accidental property of Swinburne.

Definition 3:

Property P is an ESSENTIAL PROPERTY of a thing or a person X if and only if X could not cease to have property P and yet continue to exist.

To be continued…