Here are some musings on the nature of reality and the reality of natures, from the standpoint of Aristotelian-Thomist metaphysics (so far as I understand such hifalutin’ things). But don’t let that scare you; I think it’s going to be fun.

First, consider a statue of a dog:

What is it? Is it a dog? Clearly not; it’s a statue of a dog. It’s a hunk of (I presume) bronze that’s shaped like a dog. In plain English we might say that it has the form of a dog, but in Thomist terms that’s a mistake; a real dog has the form of a dog, but a statue has merely the shape. (More on that later.)

In fact, it’s an artifact, created by human beings to have the appearance of a dog. In terms of its behavior it remains a hunk of bronze not much different from any other hunk of bronze of the same mass. We say that it has the nature of bronze. And how does it behave given that nature?

Well, first of all it’s a body. That is to say that it takes up space and has mass. Wherever you put it, you can’t put anything else in exactly the same spot. If you drop it (in a gravitational field) it falls to the place of lowest potential.

Second, it’s bronze. It has a particular mass and density. When it falls, it hits the ground with a force consistent with its mass. If you hit it with a hammer, you might well dent it.

If you ask why it does these things, a Thomist will tell you, “Because it is its nature to behave in this way.” You might think that the Thomist is avoiding the question, and from the point of view of physics and chemistry you’d be right. But from the point of view of metaphysics, this is a serious answer. If you drop the statue of the dog, it falls: not because it’s God’s whim, or because things are falling today (unlike yesterday), or because the person who dropped it decided that falling is what he wanted, but because it is its nature to do so. That is, there’s something about being made of bronze that causes it to fall when dropped in a gravitational field. A physicist would go further, and say, “it has a mass of thus and so,” and a chemist would relate this to the alloy and the molecules involved…but note what the philosopher has done. The philosopher has said, “The behavior of this status, when dropped, is not arbitrary. It always acts the same way. It acts according to a fixed nature.”

In short, it is because the bronze of the statue has a nature and behaves according to that nature that it’s worth investigating the chemistry and physics of the thing. And it turns out that many aspects of that nature are explicable in those terms. Woohoo! Go science.

However, this particular hunk of bronze looks like a dog. Science has very little to say to this. There is nothing at all in the nature of bronze that in any way tends to make it look like a dog. We call this appearance artificial: it has the nature of artifice, so to speak. Some human being made the bronze look like a dog. But note: the bronze isn’t irrelevant. The sculptor chose bronze precisely because you can make attractive, durable statues out of it given a reasonable amount of effort. The statue wouldn’t look nearly as good if it were made out of, say, whipped cream, and it wouldn’t last for more than a few minutes (not in my house, it wouldn’t).

Aristotle tells us that in any change, there are four causes—that is, four aspects of why and how the change occurred. Let’s look at two changes involving the statue: first, the change in position we call “falling”, and the creation of the statue in the first place.

So, consider a statue of a dog that’s falling through the air. It begins 20 feet above the ground,
and on impact embeds itself in a beautifully manicured lawn.

• It’s a bronze statue that’s falling. This is the material cause.
• It’s falling because it’s bronze. It’s the nature of a hunk of bronze to fall. This is the formal cause.
• It’s falling because it’s in the Earth’s gravitational field. This is the efficient cause.
• It’s falling to the point of lowest energy potential, i.e., a dog-shaped dent in the lawn. This is the final cause. Note that there’s no sense of purpose here; but anyone can see that a hunk of bronze falling from a height is gonna leave a mark on that lawn.

Now, the interesting thing about efficient and final causes is that they can exist in chains. Suppose the statue is falling through the air because I hurled into the air using a trebuchet, purely because I was curious to see whether the resulting dent was dog-shaped. It’s true to say, then, that I’m the efficient cause of the statue falling through the air, and the final cause is my curiousity as to what will happen. Thomists would call these chains of causes accidental rather than essential, per accidens rather than per se. Yes, I caused the statue to go flying…but once it is flying that fact is irrelevant to the physical outcome. If, between launch and landing, an angry landowner shot me for lobbing bronze canines onto his lawn, that wouldn’t change the flight path and the resulting dent.

Next, consider the creation of the statue. This isn’t really one change, it’s a whole sequence of changes. First I model the statue in clay, or plaster, or stone; then I make a mold from the model; then I acquire and melt bronze, pour it into the mold, and wait for it cool. Then there’s a fair amount of finish work before the statue is complete. For simplicity, then, let’s suppose that our bronze statue is a replica of a marble statue, and think about the creation of the marble statue.

I, the scultor, take a big piece of marble, and start carving away with hammer and chisel and file. I keep going until everything that doesn’t look like the dog I have in mind is gone.

• It’s still made of marble, no matter what I do. This is the material cause of the statue.
• I’m the one making the statue (but more on this in a moment). So I’m the efficient cause.
• I’m giving the statue the shape of a dog: I’m giving the marble an accidental form. The doggy shape is the formal cause.
• I can sell the resulting statue for $2534.47, and will be able to feed my family. This is the final cause.

That’s one way of looking at it. But I could also look at the efficient and final causes in this way:

• The chisel carves away the stone. The chisel is the efficient cause.
• The stone takes on a particular shape as the end of the process. This is the final cause.

There are, in fact, chains of causes here too. I decide I want to strike just there, and my nerves trigger my muscles to move my arms to make the hammer strike the chisel to break a small piece of marble away from the statue. But oddly, this chain of causes is different from the one that led to the statue flying through the air: each of the causes in this case is operating at the same time, and if any of them were removed the end would not be reached. If I chose not to strike, or if my muscles were too tired, or if the chisel slipped from my hand, or if that angry landowner shot me in the midst of my sculpting, the statue-in-progress would be unchanged. Thomists call this an essential or per se chain of causes. I might have more to say about that later.

As you can see, there’s a lot you can say about even something as simple as the statue of a dog.