In a comment on Mythtake, and in the context of free will, I said “If I were looking to demonstrate the existence of God, it’s where I would start.” Unsurprisingly I was challenged. Red rag to a bull!
I do not hold that the existence of God can be rationally proved because God is ultimately beyond out ken: we recognise him through belief. Nevertheless, I think it is possible to demonstrate that such a belief is rationally based and that, by excluding the concept of God, we are left with questions about human experience to which we can find no other answer. I start by looking briefly at a classical argument, and I provide links for further arguments.
I summarise one line of approach which is known as the First Cause argument. It states that everything in the universe is contingent. That is, nothing in our experience exists only by reason of itself: it depends on the causes which have brought it about. We may not know all the causes (back to the Big Bang?) but we perceive directly that they are necessary. If we conceive of a universe in which everything is caused by something else, we are still faced by a need for the cause of the whole universe. Thus the explanation must lie in a first cause which exists of its own nature. We call this first cause God. Note that here Aquinas, in this context, does not describe God, nevertheless it is possible to identify the necessary attributes of such a first cause, e,g., omniscience, omnipotence, personhood etc.
An argument like this requires two factors. The first is our perception that entities require causes. This is a priori because, as a principle, it requires no empirical evidence. The second factor is our experience that entities do exist, and do require causes. Of course anyone is free to claim that entities do not require causes, but I think we can safely leave these in a little group talking to each other.
There are of course other arguments such as the argument from design and St Anselm’s ontological argument, (and you may well want to raise these in discussion) but I go directly to my claim that free will (and moral obligation) provides a starting point in considering the existence of God. I do so because both characteristics are facts of human experience and believed by everyone.
Believed by everyone? Surely not! There are many people in society from committed secularists to top neurologists who do not believe in free will. And there is a similar group (perhaps the same people) who hold that our moral sense can be explained by emotion. It appears, however, that these claims are merely intellectual. In practice such people show through their everyday behaviour that in fact they believe in both.
We only have to look at human behaviour. We act and speak the whole time in a way which shows that we accept free will. Even the most died-in-the-wool secularist will not restrain himself from blaming religion for its historical malefactions – cheerfully forgetting that he claims that religions cannot be blamed since their actions were determined and therefore not their responsibility. And of course no scientific conclusion carries weight if it is merely the outcome of unverifiable causes.
The sense of moral obligation also has difficulties. It is true that great philosophers, such as Hume and Ayer, claim that our moral sense is founded in emotion, rather than in a recognition of good and evil. But a similar inconsistency is present. Emotions, as such, cannot lead to truth. Only the recognition of right and wrong can do that. Yet secularists are often miffed by allegations that they do not accept moral obligation — again cheerfully forgetting that in their appeal to emotion they have removed obligation from the equation.
Do these considerations of free will and moral sense lead us inevitably to the existence of God? No, but they do open important questions. They confront the secularist with the problem that, in accepting only empirical facts, he is omitting the facts of human experience – facts which his own actions and insights clearly display. So we may hope that in exploring the qualities of freedom to act outside material causality and his deep instinct to follow the good and reject the evil, he will edge a step or two nearer to knowing the nature of God. It’s a start.
Aquinas on arguments for the existence of God. http://web.mnstate.edu/gracyk/courses/web%20publishing/aquinasfiveways_argumentanalysis.htm
Other arguments. http://www.iep.utm.edu/design/#SH1c
Ontological argument, http://en.wikipedia.org/wiki/Ontological_argument