Continuing on in the Feser book (The Last Superstition), I found an explanation of the First Cause argument for God’s existence, which showed me that I had been misunderstanding it for years.
The explanation hinges on the difference between an accidental series of causes, and an essential series of causes. An accidental series of causes is one in which the earlier causes need no longer exist in order for the series to continue. The example Feser gives is a series of fathers and sons: A father begets a son, who begets a son, who begets a son, etc. Without the first father begetting his son, the last son would not exist, and therefore could not continue the series of fathers and sons. Yet, if the first father dies, that doesn’t prevent the last son from begetting yet another son. Thus, although the first father is a part of the causal series, his continued existence is not necessary for the continuation of the series; it can continue without him.
On the other hand, an essential series of causes is one in which the first, and every intermediate member of the series, must continue to exist in order for the causal series to continue as such. The illustration is a hand holding a stick which is pushing a stone. If the hand suddenly withers, losing its power of motion, then the stick in turn will stop moving, and so will the stone. Thus, the causal series will come to an end. The hand has to exist at the same time as the stick and the stone, in order for the causal series to continue; i.e. for the stone to continue being pushed by the stick moved by the hand, stone, stick and hand must all exist in the present.
In my ignorance, I had always understood the First Cause argument as referring to an accidental series of causes. I thought the argument was that everything that exists was brought into existence by something else, which in turn was brought into existence by something else, etc., and that there had to be a first member of this accidental causal series which got the series started. Using the illustration of the father/son series mentioned above, there had to be a first father, otherwise there could not have been a second or a third one, and therefore no fathers and sons existing today.
But Feser says no, Aquinas is talking about an essentially ordered causal series, not an accidentally ordered one. The accidental series implies that the universe had to have a beginning, but Aquinas, says Feser, never argued that it had to have a beginning. He believed that it did (says Feser), but he did not believe it could be demonstrated philosophically.
The argument, then (as I understand it), is that *here and now*, everything that is in motion is part of an essentially ordered causal series. As explained above, this means that every member of the series has to be in existence right now, or the series comes to an end.
Going back to the stick example: the stone is moved by the stick, which is moved by the hand. But we know the hand itself is not the first cause in the series. The hand is moved by the arm, which moves as a result of electrons flowing in the nerves, as a result of neurons firing in the brain. We may not know the precise order of causes in the brain, but in any case, the reason one cause follows another in the brain is due to chemical and electrical reactions. The chemical and electrical reactions are the result of the molecular and atomic behavior of the matter that makes up the brain. The activity of the molecules and atoms, in turn, are the result of, I don’t know, gravity, electromagnetism, strong and weak forces (whatever those are), etc. And those are the result of … ?
A premise of the proof is that everything that moves has a cause. Nothing moves itself, but everything is moved by something else. We may say that human beings and animals move themselves. But when you get down to it, we are dependent on things outside us to keep us moving: Air, water, food, gravity, electromagnetism, strong and weak forces, etc. In other words, we are not first causes. We do cause some things, but we are also, ultimately and fundamentally, caused.
That everything has a cause, is also the overarching presumption of science: Science takes things and asks, “What causes this?” It never looks at things and says, “We won’t bother trying to understand this since it’s not likely to have any cause.” Therefore, even when we get down to electromagnetic forces and subatomic particles, we’re still looking at things that are caused by other things.
But the point of the proof is that in an essentially ordered series of causes, one thing being caused by another can’t go on forever. As in the hand/stick/stone example, there has to be a cause that has the power of motion or change in itself.
This brings up the definition of “motion”. Feser says that “motion”, to Aristotle and Aquinas, meant not just the movement of things from one place to another but, more basically than that, it meant “change”. If you think about it, all change involves motion. If our bodies were not in motion in countless ways — respiration, blood circulation, digestion, sensation (the movement of electrical impulses along nerve pathways) — our bodies would not change: we would not grow, get a suntan, get gray hair, gain weight, etc. So it seems clear to me how “motion” and “change” can refer to the same thing.
In any event, everything that is in “motion”, i.e. undergoing change, has that change caused by something outside itself. Going back to our bodies, again some change is a result of bodily functions, and of our choices to do certain things (like drink beer and eat hot fudge sundaes every day for a week). But at the same time, having the ability to make choices at all, depends on our remaining alive, and we can’t do that without relying on things and forces outside ourselves — each of which, in turn, relies on some other object or force to keep it moving in the way it naturally does.
So as I was saying, as in the hand/stick/stone example, there has to be a cause that has the power of motion or change in itself — meaning, something that is not moved by outside forces. Because if it is moved by outside forces, then it doesn’t have the power of motion or change in itself, being reliant on outside forces to keep it moving.
Look at it this way: In the hand/stick/stone example, neither the stick nor the stone is sufficient to account for the movement of the stone. Take away the stick, and the stone will just sit there. Take away the hand, and the stick will fall to the ground next to the stone, and they will both just sit there. Neither the stick nor the stone itself can account for the movement of the stone. What accounts for the movement of the stone (when the hand is moving the stick, which is moving the stone) is the movement of the hand, which is the only thing in the series capable of moving the other two things. Thus it’s really not the stick moving the stone, but the hand which is moving the stone, using the stick as an instrument.
But even the hand can’t be the first cause in this essential series of causes, because the hand is moved by something else, which is moved by something else, which is moved by something else, and so on — but not to infinity, because if the series went on to infinity without ever reaching a cause which was not moved by something else, then everything would “drop to the ground and just sit there”, figuratively speaking, since none of them is capable of movement without being moved by something else. Every essentially ordered series of causes has to have a “hand” to get the series moving, since nothing else in the series is capable of moving itself.
The “hand” is called the First Cause, i.e. God.
P.S. This may sound like everything in the universe, including ourselves, are just God’s puppets. But that doesn’t follow logically. As I said, our bodies depend on outside things and forces to keep them alive, yet we’re still able to choose what actions we will perform with them. The point is just that the motion of which our bodies are capable, is dependent on causes outside itself in order to “keep moving”, i.e. stay alive and therefore able to make choices to behave in different ways.