If I walked up to you and there was a blue sphere hovering beside me, I’m sure you would be quite confused, perhaps even afraid. What if I then told you, “This blue sphere is quite remarkable. When the temperature goes up, it spins clockwise on its axis. When the temperature goes down, it turns red.” And, lo and behold, it does exactly what I said it would.
Certainly any reasonable person would then wonder what internal mechanism within the sphere causes it to do these things. Perhaps it has some silent, hidden jets that cause it to hover? Some special electric-powered paint that changes color? You would probably ask me, “By what power does it do those things?”
What if my response was, “It does those things because of its nature. The nature of this blue sphere is to spin clockwise when the temperature goes up, and turn red when the temperature goes down. There is no use wondering what internal mechanism causes these changes, because it is an irreducible, blue sphere. There is nothing of interest on the inside.” Sounds pretty unreasonable, right? We are not trained to look for things with irreducible qualities and natures these days; we are always prompted to take things apart to figure out how they work.
But then again, what about at the “ground level” of reality? Let’s take science’s current “tiniest thing” or “building block of nature.” Electrons, quarks, strings, whatever. Is it the case that this building block simply does what it does because of its nature? Is there a level where there is no point in trying to seek for an internal mechanism that causes a thing to behave and change the way it does? If this seems unreasonable on the macro-level of my hovering blue sphere, then why is it suddenly reasonable on the quantum level?
I would say that this question, without a doubt, was the driving factor in me trying to figure out metaphysics. Even though I am a simpleton at philosophy and metaphysics and logic, I still have this burning desire to get to the bottom of things and at least find an explanation that makes the most sense of the universe. All of the explanations – an appeal to an object’s nature, an appeal to the “laws” of nature itself, or an appeal to an infinite regress of explanations – seem prima facie ridiculous to me, but something has to be true.
But if a person simply believes that a building block “has” a nature that drives its “behavior,” this allows Aristotle’s foot in the door, so to speak. It means that on some level of reality, we cannot appeal to a lower level to explain things on a higher level. However there is still a question of whether or not formal causation happens on higher levels. This tension has been pointed out by one blogger I know of.
For me, it answers a broader range of questions to accept that formal causes occur in higher levels of reality. To use a classic example, water has properties that neither hydrogen nor oxygen have (for instance, wetness). If water has a nature that cannot be fully explained (and the key word is fully) by a simple appeal to the combination of its constituent parts, then why not treat water as an irreducible substance? Once we allow formal causation on the quantum level it doesn’t seem quite so ridiculous to look for it on every level. But I could be wrong.