Alright, now I’ve FINALLY gotten that post on Aristotle off my chest. Well, okay, since I’m dividing this into parts I still have more to do. But still, it’s progress.
Now, the word “metaphysics” has a pretty bad connotation nowadays. People apply the word “metaphysical” to things like psychic energies and whatnot. But in the context of philosophy, this word has a different meaning. In fact, the philosophical meaning is the original one. It is the study of existence itself, its prerequisites, the rules governing it, and how we make sense of it. So really, everyone engages in metaphysical thought at some point, because everyone has some idea of what can and can’t be, and how existence is supposed to work.
However, Aristotle’s metaphysical worldview is fairly different from most people’s nowadays. If I had to boil the difference down to one easy-to-understand point, it would be their stance on the statement, “The whole is greater than the sum of its parts.” Aristotelians would affirm this, while most people nowadays would say that nothing is any more or less than the sum of its parts. But this is ultimately an oversimplification. So without further ado, let’s jump right in to the gory details.
The starting point of Aristotelian metaphysics is the question of how change is possible. For example, consider an apple changing from green to red. The question here is: Where does the redness come from?
This might seem like a stupid question, but the idea behind it is pivotal to our understanding of the world. Consider, for example, the way Parmenides answered this question: The redness that appears in the apple can come either from being or from non-being. It doesn’t come from being (it’s not as though the redness was just stored away in a compartment somewhere and the apple just brought it out when the time was right; the redness actually did not exist before the change happened). Nor does it come from non-being, because nothing can come from non-being. Therefore, there is nothing the redness could have come from, and therefore the apple cannot have actually turned red; the change must be illusory. And since the same argument can be applied to any sort of change, all change must be illusory.
Many ancient Greek rhetoric teachers appealed to Parmenides in justifying their teaching practices. They claimed that because this world is illusory, what we do doesn’t matter, and therefore there is no need to worry about whether one’s arguments are correct; all that matters is that the audience is persuaded. These rhetoric teachers were called “sophists,” and this is where our pejorative use of the words “sophist” and “sophistry” comes from.
So this question actually has implications for what exactly we think the world is and how exactly we think it works, and our conception of the world can have implications for our views on morality. So this question might actually be a big deal after all.
Now getting back to the apple: Aristotle came up with an alternative response to Parmenides’s. That response was that the redness existed potentially before the change occurred, and was brought into actuality through the change. And the same can be said for any kind of change: the result of a change exists potentially before the change occurs, and is brought into actuality through the change.
Notice, first of all, the difference between this answer and Parmenides’s. Parmenides thought that the redness did not exist at all before the color change, while Aristotle says that it it did really exist before the change, though only potentially.
And note also that this answer is phrased in terms of concepts more fundamental than atoms, chemicals, etc. It’s similar to the practice in math where you assume as little as possible about your variable so that whatever you prove about that variable is as general as possible. A proof that starts with a generic odd number and shows that it can be written in the form 2k+1 shows that all odd numbers can be written in the form 2k+1. In the same way, Aristotle says that the results of a change exist potentially before the change occurs, not specifying what sorts of change this might apply to. So, as Aristotle claims, this statement applies to all kinds of change, be it on a macroscopic scale, like with the apple turning red, or on the microscopic scale, like in the interactions of atoms.
Therefore―and this is where I’ll probably lose what few readers I have―science cannot prove or disprove this axiom. I can’t stress this point enough. It’s a pretty popular practice nowadays to say that Aristotle is outdated; I mean, come on, who believes in the four elements anymore? And the four humors? And that the sun floats in the sky because it’s light, while the earth is below because it’s heavy? I mean, sheesh! But, while Aristotle did make some scientific claims, the most important parts of his philosophy are about existence and reason themselves, and therefore are actually logically prior to science. In fact, far from disproving the idea of potentiality, science actually presupposes it!
To see why, consider how a chemist would respond to the question of how apples turn red. He would say that there was some sort of green chemical in the skin of the apple, and the atoms in that chemical became reconfigured to turn into a red chemical. (Notice how I’m using general terms here.) But here our old question just pops up in a new form: Where did the red chemical come from? Well, it’s not like it really “came” from anywhere. The red chemical was just one more form that the green chemical, with its atoms mixed and matched with the atoms of a few other chemicals, was capable of taking.
But notice the language of potency in this answer: “one more form that the green chemical was capable of taking.” In other words, when making this answer we are presupposing that the way a thing exists in the present determines how it might possibly exist in the future; that a given thing is predisposed toward acting or changing in certain ways, to the exclusion of others, by what it is and what processes it undergoes in the present. This simply is what Aristotle means by potency―the possible outcomes “pointed to” by actual things. Any time you say “I can do that” or “That’s impossible,” you are making use of this concept, and therefore thinking in terms of what Aristotle means by potency.
Now, at this point, you might be thinking, “Just because I believe that the way a thing is now affects the ways it can change, doesn’t mean I have to believe in some kind of vague, shadowy middle state in between existing and not existing.” Well, I don’t know about you, but that’s the objection I would feel inclined to raise if I were the reader and not the writer here. The idea that the way a thing is now affects the ways it can change seems pretty obvious and intuitive, but the idea of potency being a real thing sounds absurd.
So let’s try to elucidate this idea. First of all, there’s the question of how there can be a state in between existence and non-existence. The answer to this question is actually pretty simple: There is no middle state between existence and non-existence. Aristotle himself explicitly stated this in what we now refer to as the Law of Excluded Middle: A thing must either be or not be; there is no way it can do both, neither, or a mixture of the two. This is one of the three laws that are presupposed by all rational thought, and therefore can neither be proven nor disproven―any proof or disproof would have to presuppose these laws and would therefore be presupposing what it was trying to prove/disprove. (The other two are the Law of Non-Contradiction―nothing can both be and not be at the same time and in the same respect; and the Law of Identity―any given thing is itself and nothing else. Just try to prove or disprove any of these, and you’ll catch yourself presupposing it every time.)
It’s easy to make the mistake of thinking that potency is in between existence and non-existence; I’ve made that mistake myself, which is why I guessed that that’s probably the objection that people will bring up. But Aristotle’s thesis here isn’t that there’s a third state besides existence and non-existence; rather, his claim is that existence is not a single monolithic category―it is divided into actual and potential existence.
To see that potency is a kind of existence, consider a block of wood and a pool of water. The block of wood is capable of being formed into a statue; the water is not. Now, this capability is something that is in the wood here and now, but that the water lacks here and now. In other words, this capability is a real feature of things that any given thing can either have or not have.
Again, appealing to science doesn’t change anything. Even if someone said, “The wood’s molecules are packed closely together and therefore retain their shape, whereas the water’s molecules are only loosely connected and therefore slip out of any shape they’re put into,” this would only be moving the problem somewhere else. In this case, the wood molecules are capable of forming a tight, firm bond with other wood molecules, whereas the water molecules do not have the capability to do this with other water molecules, unless you lower their temperature. Again, we are brought back to the idea that the capabilities of things are real features that can either be or not be in any given subject. Taking things even further and talking about individual electrons and protons will just bring up the same thing again.
And so, if all of that was convincing to you, then we have finally arrived at the idea of act and potency, the two words that sum up all of Aristotelian metaphysics just as supply and demand sum up all of economics. The usage of these words in this sense is pretty archaic, but as you can probably guess, “act” refers to actual existence (being “in act”) while “potency” refers to potential existence (being “in potency”). “Act” might seem like a strange name for “actuality”―although they’re from the same root, their meanings aren’t really considered to be related in modern English―but it makes sense on a certain level because one of the key differences between actuality and potentiality is that only actual things can be causes. If a thing’s cause is only potential and not actual, then it won’t occur. So potential things can’t “act.”
Now, this theory has a lot of implications, not all of which are exactly popular. In fact, I would argue that it’s because of these unpopular implications, and not because the theory is actually defective, that scholars have abandoned it. But those are topics for another time. If you want to read more about Aristotelian metaphysics, I would highly recommend Edward Feser’s Scholastic Metaphysics: A Contemporary Introduction. Pretty much everything I know about metaphysics, I learned from Feser. Feser’s blog also has a lot of posts on individual questions of metaphysics. This free online book (starting at chapter 4) is also a great resource.
EDIT: Just realized, in the second paragraph, instead of writing “The whole is greater than the sum of its parts,” I accidentally wrote “The whole is greater than the part.” And I never noticed for a whole year. Well, that’s embarrassing.