I finally made it to Aquinas’ “Five Ways” today in my reading of the Summa Theologica. That isn’t too impressive if you know the structure of the book; I’m still in the first 1%. However, I’ve enjoyed what I’ve read so far. Keep in mind that I am no expert here.
Aquinas determined five major categories of justification (or Ways) for God’s existence in writing the Summa. The first is by means of cause and effect; that is, objects set in motion require a cause. A recurring theme is that you cannot have an infinite regress – in this case of objects setting others in motion – because then there would be no original mover or Prime Mover, so there would be no motion. This doesn’t pertain simply to physical motion, but to any movement from potentiality to actuality (say a thought to an action or a piece of tinder to a fire). The Second Way revolves around efficient causes. I am perhaps a bit behind on my terminology, but I had a hard time distinguishing this from the First Way. From what I can gather, this Way has in mind particularly the necessary causes and their intermediate steps from start to finish in a chain of causation. Again, just like with the First Way, an infinite regress is not possible, so a First Cause must exist.
The Third Way involves possibility and necessity. There are many things in nature that we can observe that either -are- or -are not-. That is, they are possible to -be- or -not to be- (as one fairly famous Englishman put it). This argument says that since all things are possible -not to be-, there could have been a time when nothing was in existence. But from nothing, nothing proceeds. Something cannot exist if nothing exists. But nothing is not in existence; something is. So we know there was never a time when nothing exists. So, there must be something that requires its own existence. Something that is necessary. A Necessary Existence. Aquinas suggests we all refer to this when we talk of God.
The Fourth Way is subtle, but thanks to some experts on Aquinas, I have a reasonable understanding of it. It applies to those things which can be gradated. An example is temperature, which can either be greater or lesser. The argument goes that things are predicated according to how much they resemble their maximums. Aquinas suggests that it is this maximum which is the cause of the attribute in all the lesser examples. Fire, the maximum heat. God, the maximum goodness and all other perfections. Dawkins I believe commented on this argument using “smell” to mock it, but in doing so misread the conditions of the argument and proved himself to be somewhat short when it comes to philosophical matters.
The Fifth way regards the design inherent in the world. Until recently (and even recently in less rabid circles of materialists), design is assumed in the universe by its obvious presence. There is argument over its cause, but not its existence. Aquinas puts all of these sorts of claims together and suggests that an intelligence is required for such design where all things in nature tend towards a certain end.
Aquinas goes on to respond to typical doubts of God’s existence; the problem of evil (addressed by Augustine) is dealt with by suggesting that finite evil is more than made up for by its transformation into infinite good, whether we see it or not. The problem of reducing reality down to materialism (or some variation) is dealt with by reference to the necessity of an immovable, self-necessary first principle, Prime Mover, First Cause, we call God.
This is just one small section of a massive work, but I found it fascinating as many Christians have never even heard these arguments articulated; or at least, not all of them. And to know they were written down centuries ago and are still powerful today is quite a feat for anyone to perform. I look forward to reading the rest and commenting when I can.