The First Way

Hello everyone and welcome back to Deeper Waters. I’d like to thank first off Joel for his appreciation of last night’s post. That doesn’t happen often, but sometimes someone does raise a profound point that I want addressed. I hope it was to your satisfaction. I’d also like to thank Paul who left a comment and seemed to certainly be satisfied by it. I do recall when I first began doing apologetics that I thought people would convert in droves once they saw the evidence.

That delusion doesn’t last long.

We’re talking about the doctrine of God and tonight, we’re going to start looking at God’s existence based on the Summa Theologica of Aquinas which can be read at We’re going to begin going through his five ways. However, I ask for your prayers before we go on. First, I ask that you pray for me in my Christlikeness. Bluntly, I have a problem with perfectionism and I seek to get past it. Second, for my financial situation. Third, I ask for prayers for a third related area in my life. Let’s get to the argument now.

Let’s define some terms first off. To begin with is actuality which simple means that which is. It is referring to a capacity already realized. Next is potential, which is the ability to change. There is passive potential which is based on receiving change from another and active potential which is about an agent performing an action that does not necessarily affect that thing’s essential nature.

As for motion in this argument, we could be tempted to think of motion in purely material terms. We might think of Newton’s laws of motion for instance. That is not what Aquinas has in mind, although it doesn’t rule out such motion. It would be included. Aquinas has in mind simply change of any sort.

Now Aquinas has stated that something cannot be in potential and be actual at the same time in the same sense. It can be actually one thing and potentially another but it can’t be actually one thing and potentially the same thing. Something that is actually hot cannot be potentially hot. It can have the potential to be hotter, but that is a difference of degree and not of kind.

However, the moving from potentiality to actuality always comes from something else in some way. It is the fire that makes the stick hot. The stick does not make itself to be hot. This is because once again it cannot be actual and potential in the same sense at the same time.

Aquinas says that this cannot go on indefinitely as there cannot be an infinite regress of movers. Actuality has to come from somewhere. Thus, Aquinas says that at the end, there is an unmoved mover who is responsible for the existence of change yet he himself is unchanged (A point he will expound on later) and this everyone knows to be God.

When we get to the immutability of God we will expound this more, but the problem of change was a great problem from the ancient to the medieval period and Aquinas’s answer here is addressing that. How do you explain the existence of change and continuity? We’ll get some background on that when we get to immutability.

For now, this is Aquinas’s first demonstration to show the existence of the unmoved mover who is pure actuality.

Tomorrow, we shall look at the second way.

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