The Four Causes

A Little History

Despite attending multiple colleges and universities and obtaining two degrees, I did not encounter Aristotle’s “four causes” until several years after I had graduated. The few philosophy courses I took spent brief moments discussing Plato before moving 2400 years into the future to spend the rest of the time talking about modernism and postmodernism (one class in particular focused on the professor’s own written material).

I’ve since learned how much of a waste those classes were. The real meat of philosophy is in the ancient, medieval, and early modern world. There have been few philosophers since who have contributed anything of the magnitude that their ancestors did, and often their contributions led to errors repeated for generations. If you want to study good philosophy – and to paraphrase CS Lewis, you should want to study good philosophy if only to answer bad philosophy – you should start at the beginning. Not everything Plato or Aristotle or their successors said was correct, but you can learn a lot even in disagreement.

What Are the Four Causes?

Aristotle in particular had a conception of how to explain the nature of anything and everything, called traditionally the “four causes”: material cause, formal cause, efficient cause, and final cause.

Consider the human eye for a moment. The material cause of something is the matter of which it is composed, so the material cause of an eye is the various molecular components which make it up. The formal cause of something is the shape or form it has. For the human eye, this includes the overall eye itself as well as the parts which make it up, from the iris, pupil, and lens to the retina.

An efficient cause is like the history of how a thing came to be. A human eye begins to grow early during pregnancy. The whole story of how the eye came to be where it is at the moment you consider it is part of this efficient cause. Finally and fittingly, there is the final cause. This is the telos or “end” of an object; it’s purpose. The purpose of the human eye is to see.

These four causes constitute a comprehensive explanation for anything you can think of, and virtually anything you can know about an object will fall into one of the categories. While this might seem esoteric, consider a very practical use of this information for a human eye.

In medicine (at least medicine traditionally understood and not the postmodern “choose your own adventure” style we increasingly see in mental health and now even in physical health), the goal is to first “do no harm”, but ultimately to mend things that are not working. A human eye can have any number of defects. To know what constitutes a defect, you first need to consider what the final cause of an object is; in our case, sight. So an eye that cannot see well or is blind to color or blind to everything is unhealthy, for it is not capable of realizing its end. Medicine which corrects these problems and enhances vision (be it surgery or contact lenses; even sunglasses depending on the situation) may be “unnatural” in the sense that it is developed by human beings – being artificial (from Latin artificium; a thing people make) – but it is not “unnatural” in the more important sense of going against the nature of the object in question. Medicine which restores sight to a blind person or which corrects nearsightedness restores natural function, because it enables the final cause of the object to be realized. In this sense, good medicine is eminently natural. Obviously, a good knowledge of the formal, material, and efficient causation of an eye is required to develop medicine as well.

An Interesting Discovery

In his book “Summa Philosophica”, Peter Kreeft answers the question “Whether there are four causes?” in his section on cosmology. He answers in the affirmative, but one of the notes he made helped me realize that even if today we don’t discuss the four causes in the language I used above, we still talk about them in language very similar to it. He proposes this objection to the idea that the four causes exist:

We no longer use the word “cause” to refer to the two internal elements or dimensions that Aristotle called “formal” and “material” causes.

He responds, in part:

We still use the word “because” for all four causes, even though we no longer use the word “cause” for the first two. E.g. we say that an enclosed plane figure is a triangle “because” it has three angles (formal causality), or that paper towels mop up liquid “because” of their capillary structure (material causality).

My entire life, and likely yours as well, you’ve used the language of the four Aristotelian causes and have never even noticed.

A triangle is a triangle because it has three sides. (formal causality)

A bullet pierces because it is made of metal. (material causality

A car is in your garage because you drove it there. (efficient causality)

An eye is healthy because it sees. (final causality)