Subtitle: how a modern physicist is liable to misunderstand Aristotle. This post was inspired by a very interesting post by Edward Feser here.
I have tried. What follows is my attempt to give full expression of my own ignorance. One of the conclusions I have drawn from my forays into Ancient and Medieval philosophy is that these are great thinkers.
Here is the standard illustration for Aristotle’s four causes. Consider a marble statue. The statue has four causes. The material cause is the marble, the material out of which the thing is made. The formal cause is the arrangement of the statue, its geometrical shape. The efficient cause is the “doer”, the sculptor, who arranges the material into the desired shape. The final cause of the statue is the purpose for which the sculptor has created the statue, e.g. to look beautiful in the garden.
Aristotle and Newton
Right, I think. My physicist training naturally has me try to cast my Newtonian (occasionally Einsteinian, sometimes quantum) view of the world in these categories. (This might be a bad idea, I think, given the discontinuity between Aristotle and Newton. Still, I’ll give it a go. Also, I’ll worry about relativity and quantum mechanics later, if at all.) So,
- Material cause – the particles of matter out of which physical things are made.
- Formal cause – the arrangement of those particles. Mathematically, a list of the position and velocity of each particle at some time
- Efficient cause – Newtonian forces, which move particles around.
- Final causes – an emergent, higher-level property of minds, who can make and execute plans.
(This is not the correct way to understand Aristotle, so stay tuned.) So far, so good, I think. The “Newtonian” material, formal and efficient causes give all the information one needs to solve Newton’s laws of motion. But now the confusion starts.
A lecturer giving an introduction to the history of science talks about Plato’s theory of forms as a realm of abstract but still “really” existing ideas. He later seems to suggest that the formal cause of a chalk circle drawn on the board is the idea of the circle in the mind of the lecturer. I ask, “For the circle on the board: is the formal cause the idea in the mind, or the idea of a circle floating out there somewhere in Plato’s realm?”. “Uh … have you been reading the Scholastics?”, he replies. “Nope”. I can’t remember the rest of his answer – it was rather vague. I’ve had a chance to ask a few other philosophers about formal causes since, and their reply usually starts with a grimace.
So it was that I came to Edward Feser’s Aquinas (A Beginner’s Guide). His exposition is admirably clear, and it is obvious that I must change my understanding of the four causes. In particular, final causes are more than just intentions of minds. There are natural final causes. When a match is struck and fire is created, the efficient cause of the fire is the match. At the same time, the final cause of the match is the fire. The properties of the match “point to” or “are directed at” the creation of fire. Fire is what matches do. The match isn’t just a generic efficient cause that could cause any old thing but just happens to cause fire every time. Its ability to do something is controlled by fire as its final cause. I picture this as the efficient cause being the engine, and the final cause as the steering wheel. The efficient cause does the causing, and the final cause directs the efficient cause towards the production of its effect.
The shocking thing about this, as Feser points out, is that the scientific revolution, despite its PR, didn’t get rid of final causes. Final causes are how Aristotelian metaphysics explains the orderliness of nature. The fact that things keep doing the same kind of things – trees grow, the sun shines, fire burns, dropped stones fall – is because the efficient causes in the world are conjoined (is that the right word?) to final causes, ensuring that they produce consistent effects. The “laws of nature”, to use an slight anachronism, are more about final causes than efficient ones. But that is a topic for another day.
Despite Feser’s clarity, formal causes now get even more confusing. Feser argues that things can be imperfect instantiations of their form. Their form isn’t just how their parts are arranged. It is, in some sense, how they should be arranged, what their essential arrangement is. For example, when a person loses a leg, they don’t take the form of a one-legged person. Their true, two-legged human nature is still there in the person, but it is instantiated imperfectly.
Note that Aristotle differs from Plato in locating the form of a thing in the thing itself, not in some ideal external realm of forms. It isn’t just that the person fails to replicate the ideal of a two-legged Platonic person “up there”. The one-legged person still has the form of a two-legged human. Two-legged-ness is still in there, somewhere.
How do we see the form?
Here is my specific confusion. Feser asks us to consider a drawing of a triangle. This drawing of a triangle has the form of a perfect triangle. That is, its form is perfect triangularity. It can instantiate this form more perfectly (a sharp pencil, a straight edge and some graph paper) or less perfectly (a crayon, free hand, on a cracked plastic bus seat). Remember: we’re talking about the form of that specific collection of ink/crayon, not the abstract idea that it usually represents.
Now consider a triangle with sides sides that bow outwards slightly. Why say that this is a mildly imperfect triangle, rather than a slightly imperfect Reuleaux triangle? Consider a sequence of geometrical shapes (below), starting with a circle and smoothly merging into a triangle. (Consider these as real, physical things, not as mathematical abstractions. Print them off, and then consider the arrangement of ink on the page). At what point does it cease to be an imperfect circle and start to be an imperfect triangle? All we have is an arrangement of ink. How do we see through it into the perfect form behind it?
The forms of things can change. How do we know that Terri Schiavo (Aquinas, pg 203), having entered a vegetative state from which a return to consciousness was not physically possible, still had the form of a human (a rational animal) even though she could no longer exercise her rational capacity? Why not instead believe that she had, in having brain damage cause by a cardiac arrest, changed her form to become something else, something less than human? (I wish I had an example which didn’t have such strong moral consequences, but that is the example Feser uses.)
Feser criticises Descartes’ dualism on the grounds that it creates the problem of personal identity: since a person’s soul is immaterial, it is imperceptible. “All we ever observe or can observe are people’s bodies, not their souls, not them. How we can ever know whether other minds or persons even exist at all thus becomes problematic.” (pg 204). But it seems that Aristotle has the same problem. Given that “any material thing is bound to fail perfectly to instantiate its form in some respect or another”, it becomes somewhat arbitrary to decide which particular perfect form a particular object is failing to instantiate. What would you expect to find inside a packet of “Almost Bacon”?
Sometimes, when something changes, we are to say that the matter has taken on a different form, as when a rubber ball is melted down into an eraser. Other times, when something changes, we are to say that it has become a more or less perfect instantiation of the same form, as when a person loses a leg but remains the same person. The choice between these two characterisations seems to be somewhat arbitrary. For every clear example, there will be a thousand ambiguous ones.
Another problem. According to Aristotle, one of the features of formal causes is that they permit one to truly think about something, since the form of a thing can exist in the object and in the mind at the same time and be the same thing. However, if, when I consider a triangle, the same form exists both in my mind and in reality, then we have a problem. If the crayon triangle on a seat is an imperfect instantiation of a perfect triangle, then its form is that of a perfect triangle. So if I think about the crayon triangle, what I am really thinking about is perfect triangularity. But then I am not thinking about the crayon triangle on the seat. I cannot think about the triangle on the seat. I can only abstract from that triangle to perfect triangularity.
The problem for the physicist
Feser wants to return modern science to an Aristotelian metaphysic. It is, despite my misgivings, a project for which I have some sympathy. I can see, or I think I can see, some of the benefits for such a system.
The problem is that I can’t see how to analyse the theories of modern physics in Aristotelian terms. The examples used – sticks and hands and stones and fires and matches and such – are somewhat useful, once one has a firm idea in mind of what they are trying to illustrate. But I can’t translate the principles into, say, quantum field theory. What, in a quantum field theory, corresponds to “form”? What are the “potentialities” and what are the “actualities” in a given configuration of fields? How do we understand causes in spacetime? If I had two bodies in otherwise empty space orbiting each other (according to Newtonian gravity), what is the first cause?
The problem with something like the triangle example is that these ideas seem to be adding structure on top of the physical theory. As well as the atoms and such that make up the crayon triangle, there is also “perfect triangularity” hanging around, somewhere. The physicist in me wants, to make these ideas precise, a function that takes a certain configuration of fields as an input, and outputs its true essence, or form, or whatever. This would seem to have to make arbitrary distinctions – if the sides bow by 4.7% or less then it’s an imperfect triangle, more than 4.7% and it’s something else. Physicists, for obvious Occam’s razor reasons, are loathe to add empirically unobservable structure to their theories. General relativity is hard enough as it is without having to analyse the true form that inhabits some spacetime.
In particular, as physicists we are taught to avoid debates over names and labels. Feynmann summarises this view perfectly:
You can know the name of a bird in all the languages of the world, but when you’re finished, you’ll know absolutely nothing whatever about the bird… So let’s look at the bird and see what it’s doing — that’s what counts. I learned very early the difference between knowing the name of something and knowing something.
These discussions of instantiations of triangularity strike me as debates over the name of something. “I say it’s a more perfect Reuleaux triangle”. “Well I say it’s a less perfect triangle.” This, and all other discussions of forms and patterns, seems like a debate about how I will classify something in my mind. Such classifications can be more or less useful but, like our naming of a bird species, don’t reflect anything about the real world.
Confusion, not criticism
Anyway, such are my confusions. Note well: these are not necessarily criticisms. I’m pretty sure I’m just not getting it. Aristotle and Aquinas were geniuses, and so presumably have answers to my questions. Still, I think that the points made above are somewhat typical of how physicists react to Aristotle’s ideas. The neo-Aristotelian project, to recruit physicists, will have to deal with these kinds of confusions. I couldn’t help thinking throughout Feser’s “Aquinas” that I would be greatly helped by an appendix titled: “1001 examples of how Aristotelian metaphysics analyses familiar and fundamental physical systems”.