Aquinas' Five Ways
Thomas Aquinas proposed five arguments for God in the thirteenth century, and modern Christians still hold them up as good. He did not claim they are proofs, though they are often called that (eg here ). Indeed, they could be seen as arguments for the nature of God. We know God exists, but what can we say about him? They are somewhat obscure, perhaps reflecting medieval philosophy, and people do argue about exactly what they are. I have to qualify this post by saying that this is my understanding of them. I resever the right to update this page if I learn otherwise. Argument from motion The first is the argument from motion, by which Aquinas means change. All change happens for a reason, and that reason is itself a change. Therefore there is either an ultimate "unmoved mover" or an infinite regress of changes. One problem is that not all change has a reason. Things do happen spontaneously; we know this from quantum mechanics, Atoms of radioactive elements do just decay...