To loqi and Nesov: Again, both of your responses seem to hinge on the fact that my challenge below is easily answerable, and has already been answered: [...] To loqi: Where do we draw the line? Where is an entity too complex to be considered fundamental, whereas another is somewhat less complex and can therefore be considered simple? What would be a priori illogical about every entity in the universe being explainable in terms of quarks, except for one type of entity, which simply followed different laws? (Maybe these laws wouldn't even be deterministic, but that's apparently not a knockdown criticism of them, right? From what I understand, QM isn't deterministic, by some interpretations.) To Nesov: Again, you're presupposing that you know what's part of the territory, and what's part of the map, and then saying "obviously, the territory isn't affected by the map." Sure. But this presupposes the territory doesn't have any irreducible entities. It doesn't demonstrate it. Don't get me wrong: Occam's razor will indeed (and rightly) push us to suspect that there are no irreducible entities. But it will do this based on some previous success with reduction-- it is an inference, not an a priori necessity.