Back in the day, from philosophers like Aristotle (in his Metaphysics) to theologians such as Thomas Aquinas, our best thinkers worked hard to develop rational proofs for the existence of God. Thomas summarized five of these in his massive book, Summa Theologica. The big five included:
- argument from motion (or 'the unmoved mover') - we see things in motion, something must ultimately cause the first motion, namely an 'unmoved mover,' who is God.
- argument from first cause (or 'efficient cause') - we see an order of cause and effect--nothing causes itself--so something must ultimately be the 'first efficient cause' of everything, who is God.
- argument from contingency (or possibility & necessity) - we can see that everything in the world can possibly be or not be, but nothing is necessary in itself. They are 'contingent.' But to cause all these contingencies, there must be some being necessary in himself: God.
- argument from degree (or perfection) - we see that everything by degrees is better or worse. There must be something perfect which causes every other goodness or perfection, namely God.
- argument from design (or teleology) - we see that everything is designed to achieve the end for which it was designed. There must be an intelligent being directing everything to that end, namely God.
Bear with me, I'm not going to try to prove God exists. Some of these arguments have been soundly refuted, then defended, abandoned or upgraded. Not my job. I don't know about 'proving God' rationally. But eventually I want to borrow Aquinas' argument for perfection to say something about God's nature, if you believe in God already as a faith statement. Aquinas' argument from perfection basically runs like this: