If there is just one level, then the explanation for everything is on that level or can be reduced to that level, so you can’t concretely envision, as Eliezer says, something that can’t be reduced.
I’m pretty sure that just can’t be right. (His argument, that is. I think your interpretation of it is dead on.) We are not limited to imagining the sorts of things our brain is causally determined by. And the way you just put it seems completely backwards. Even if everything reduces to quarks, it’s only in principle—our brains are hard wired to create multiple levels of models, and could never conceive of an explanation of a 747 in terms of quarks.
Look at it this way. Can a painting have a subject? Can it be “about” something? Of course. Certainly there’s nothing supernatural about this, but there’s also nothing legitimate on the level of quarks that could be used to differentiate between a painting that has a subject and a painting that is just random blobs. I can imagine, after all, two paintings, almost identical in their coordinate-positioning of quarks, which have completely different subjects. I can also imagine two paintings, very different in terms of coordinates of quarks (perhaps painted with two different materials) which have the same subject. So while everything reduces down to quarks, it’s the easiest thing in the world to explain a painting’s about-ness on a separate level from quarks, and completely impossible to envision an explanation for this about-ness in terms of quarks.
I’m just not sure what about a “black ball” misses the mark of conceivability.
Eliezer_Yudkowsky said:
This comes from a post from almost a year ago, Excluding the Supernatural. I quote it because I was hoping to revive some discussion on it: to me, this argument seems dead wrong.
The counter-argument might go like this:
Reductionism is anything but a priori logically necessary—it’s something that must be verified with extensive empirical data and inductive, probabilistic reasoning. That is, we observe that the attributes of many entities can be explained with laws describing their internal relations. Occam’s razor tells us that we don’t need both the higher and lower order model to actually exist, so we unify our theory. The repeated experience of this success leads us to extrapolate that this can be done with all entities. Perhaps some entities present obstacles to this goal, but we then infer that their irreducibility is in the map (our model for understanding them) not in the territory (the entity itself.) But again, we infer this by assuring ourselves that they just haven’t been explained YET—which implies it’s reasonable, based on inductive reasoning from the past, to assume that they will be reduced. Or we describe some element of the entity’s complexity that makes “irreducibility in practice” something to be expected. We therefore preserve its reducibility in principle.
But we do not (it seems to me) merely exclude its irreducibility based on a priori necessity. Why would we? It’s perfectly conceivable. Eliezer describes in an earlier post the “small, hard, opaque black ball” that is a non-reductionist explanation of an entity. He claims its just a placeholder, something that fools us into thinking there’s a causal chain where nothing has actually been clarified.
But it’s perfectly conceivable that such a “black ball” could exist. I suppose there’s no way to prove that it’s irreducible, and not just unreduced as of yet, in the same way that one can’t prove a negative. But this just presupposes that the default position ought to be reductionism. We should assume innocent until proven guilty. But which is innocent in this case: reducible or non-reducible?
So what if we come across something that appears to be a “black ball”? We attempt with all our mental and technological acuity to analyze it in terms or more fundamental laws, and every attempt fails. I would argue this is a good example of empirical evidence against materialist reductionism. We indeed have an entity that obeys laws which we can describe and predict—it just has laws that can’t be reconciled with the physical laws of everything else, and when interacting with anything else, violates them.
Occam’s razor is indeed strong here: we recognize that, given the faintest hope of reduction, we should throw out irreducibility in favor of having as few types of “stuff” as possible. This happens in the case of “elan vital.” But it seems perfectly conceivable to me that there might be an entity that’s truly a black ball.
Now this seems so massively incorrect that I fear I’m misunderstanding Eliezer. Does anyone have any feedback? I’d love to make a post about this, once I generate some karma.