Everything happens for a reason

These are things that have a purpose.

I.
Foititus: Everything happens for a reason!
Didaskalus: Why, Foititus, I agree completely. In fact, I was just pondering this a moment ago.
Foititus: Were you indeed?
Didaskalus: Absolutely. Do you see the apple, across the table?
Foititus: The green one, in the bowl?
Didaskalus: That very one. It occurred to me that it is green for a reason. Specifically, the skin of the apple contains chemical compounds that absorb red light and reflect green light. That is the reason that it is green.
Foititus: I think you are mocking me, friend Didaskalus. I think you know this is not what people mean when they say “things happen for a reason”.
Didaskalus: But it is perfectly correct! That apple is green, and the chemical compounds in the skin of the apple are the reason.
II.
Didaskalus: Aristotle said that everything happens for four reasons.
Foititus: Exactly four? No more, no less?
Didaskalus: Ask me again why the apple is green.
Foititus: But Didaskalus, you have already given your answer…
Didaskalus: Ask me again.
Foititus: Friend Didaskalus, why is the apple green?
Didaskalus: The apple is green because of the functional properties of electromagnetic radiation, and the way that it interacts with the electron shells of the atoms that make up the skin of the apple. The reason that you see green has to do with the complex mathematical relationships between energy and matter.
Foititus: I can’t argue with that. But I still don’t think that is the type of reason people are thinking of, when they say that “everything happens for a reason”.
Didaskalus: Maybe not. But it’s completely correct. It’s a valid answer to the question: “what is the reason the apple is green?”
Foititus: Maybe…
Didaskalus: Well! If you are not satisfied with either of those answers, I suppose I could also explain to you in detail the metabolic process of the growth and development of the apple, and how its greenness came about over time. The cellular development that changed it from a brown seed into the green apple that you see in front of you. Maybe this is the “reason that the apple is green” that you are looking for?
Foititus: You are teasing me, friend Didaskalus. You know very well that this is not the answer that I am looking for.
Didaskalus: Maybe not. Yet it, too, is “the reason that the apple is green”.
Foititus: I notice that you have given me three different reasons. Just for the sake of finishing this lecture, I beg you: please tell me what Aristotle’s fourth reason would have been, to explain why the apple is green?
Didaskalus: Aristotle’s fourth type of reason was what he called the “final cause”: the ultimate purpose for a thing. That is, what does God or nature hope to achieve by the fact that this apple is green?
Foititus: Finally! That’s what I’m talking about. I suppose when I say “everything happens for a reason”, what I really mean is “everything has a purpose”, or to use Aristotle’s terminology, “everything has a final cause”.
Didaskalus: Yes, I think that is what you really mean. I still don’t know, however, why you believe it.
III.
Foititus: Do you deny that components within a system can be described as having a purpose with respect to the functioning of that system?
Didaskalus: I do not deny it.
Foititus: And when talking about natural systems that undergo evolution, can we not talk about the purpose of elements in terms of their evolutionary function?
Didaskalus: Certainly we can. For example, it is sensible to say that the purpose of the heart is to pump blood and transmit oxygen and nutrients to cells, from both an evolutionary and a system-theoretic standpoint.
Foititus: Then I do not see why you would oppose that idea that even naturally-occurring events can have a final cause – a purpose. Even the greenness of the apple, for example, could be to attract animals that will eat it, digest it, and excrete its seeds far and wide, thus encouraging the reproduction of more apple trees.
Didaskalus: I am not questioning the idea of natural purpose. I agree with you that purpose can exist without consciousness or intent.
Foititus: Aha! Then I have trapped you! Everything in the universe can be understood as operating within one or more systems. Therefore, everything in this universe can be described as having a purpose in that system!
IV.
Didaskalus: What do you know about probabilistic encoding by neural populations?
Foititus: I believe that is the theory that certain concepts or stimuli are represented in the brain by a probabilistic pattern of response across a set of neurons. So, for example, although individual neurons have very noisy behavior and can appear somewhat random, on an aggregate level we see that a particular group of neurons might have, say, 80% of their neurons fire whenever you see a letter “E”, for example, or think of a cat.
Didaskalus: That is an excellent summary, yes. So, if you look at the behavior of a single neuron in that population, it may or may not fire, even in the presence of a letter “E” or the thought of a cat.
Foititus: That’s right. The behavior is probabilistic, seen only at the aggregate level of all of the neurons.
Didaskalus: So imagine one neuron that happens to not fire during one particular cat-thought. Would you say that there is a reason that that particular neuron did not fire?
Foititus: Oh. Now I see the trap you have laid for me.
Didaskalus: Not a trap! Merely a question. When you spoke of systems, before, you were thinking of deterministic systems. It makes sense when talking about wind-up clocks created in the nineteenth century. In that system, every single part of the system has a “final cause”: a purpose that is necessary to the functioning of the system as a whole.
Foititus: But you are saying that in probabilistic systems, it is different?
Didaskalus: In the brain, you cannot say that there is a purpose to the behavior of a specific individual neuron, because it is one of many items acting together with a great deal of redundancy. All that matters to the system is the population-level behavior. Each individual neuron has behavior that is governed largely by probability and randomness.
Foititus: Fine, so perhaps neurons are the exception to the rule…
Didaskalus: I’m afraid, friend Foititus, that this unhinges your entire argument. Almost every natural system behaves in this way. Flocks, swarms, groups of people, neurons, weather patterns, traffic patterns… most systems that make up this world are made up of components that are probabilistic and, to one extent or another, interchangeable.
Foititus: So what you are saying is that when people look at their social interactions, the weather, or any event that arises in a system with a large number of interacting parts… those are exactly the situations where things do not have a reason?
Didaskalus: I would say, more precisely, that there is no final cause for any particular behavior or state of a specific individual in the system. That is just not how these systems are put together. That is not even the way that good software is put together, any more. Everything comes with redundancy and interchangeable parts.
Foititus: You may be right, but I know for a fact, probabilistically, most people will never stop saying “everything happens for a reason”!
Didaskalus: Yes, I’m sure that is true.

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