onald Rumsfeld was famous for saying there are known knowns, known unknowns, and
unknown unknowns. There was even a mildly amusing book written about it (Pieces
of Intelligence: The Existential Poetry of Donald H. Rumsfeld). But Rumsfeld
forgot to say that below that, at the quantum level, there are unknowable unknowables.
Suppose, for the sake of argument, that an omnipotent deity existed. Let's call him, for want of a better name, God. Now, I haven't kept up on the latest theological pronouncements, but I gather that a plurality of theologians believe that it is impossible for God to do impossible things, like creating a rock so heavy he cannot lift it.
There is a very real reason why this must be true. It's not in the nature of ‘impossible,’ but in the fact that the very nature of causation would fracture. Take a simple example. Suppose Kansas City instantaneously disappeared or, say, turned up in Ohio. We know this is impossible by virtue of the fact that it conflicts with cause and effect; either the world can remain real or impossible things can happen. If such a miracle would happen, it'd be proof that the world is not as it appears to be.
Now, Kansas City might not be a good example. After all, there are several Kansas Cities, spares as it were. Even so, if one suddenly ceased to exist we would probably notice, and we'd propose increasingly implausible explanations for it: flying saucers, maybe, or a mysterious accident, or maybe Russian hackers or President Trump.
Of course, if the universe were rewritten so that K.C. never existed, we'd be unable to notice that. But what I'm talking about is a K.C. that suddenly, for no reason, stopped existing. You'd be driving west on I-70 and you'd think, isn't there a supposed to be a city here? Eventually you'd adapt. Maybe you'd think the people all just suddenly moved north and changed the name. Or maybe the K.C. in Nicaragua moved to Ohio somehow.
The problem with a truly impossible event, like K.C. both existing and not existing, is that it's impossible for humans even to imagine. Suppose a deity left K.C. in its original place and moved it to its new place simultaneously. That is an event that is impossible, and therefore impossible to imagine.
It's impossible to imagine because it would leave us with an inconsistent world. A network of events would spread out from the old K.C. and another network would spread out from the new one. We'd have two superimposed yet conflicting worlds, and since our minds are molded to fit a self-consistent reality, we'd be forced to choose one or the other and act and think accordingly. Even more than that, the surrounding events would also be forced to choose which causal path to follow. We would indeed have two worlds in which no event in one could affect the other.
If a deity did that, he would destroy the illusion of reality in the world, thereby annihilating his own creation. Since such an act would also be the only incontrovertible evidence we would ever have for his existence, this strikes me as a reasonable argument for agnosticism. Of course, there are other properties we might attribute to a deity, such as that he must exert continuous effort to maintain the existence of matter, sort of Atlas-like holding up the world. Theologians call this divine conservation.
But suppose the contradiction occurred on a the subatomic level, where contradictory events are believed by quantum theory to actually happen. We can now understand why some physicists postulated that a multiverse could actually exist. Furthermore, if our minds were by nature quantum indeterminate, every decision we made would create a separate incompatible universe.
That is an impossibility; despite what some have argued, the mind and brain cannot function in an indeterminate manner. Such a thing would make it impossible to reconstruct our own thoughts. As many others have argued, it would also be inconsistent with free will.
When quantum particles are superposed, they are not capable of causing different incompatible events. In fact, the reason we are puzzled by them is that they are not causing incompatible events. The fact that the spins of two particles can be highly correlated while separated by huge distances means that it is our concept of distance, not our concept of causation, that needs updating.
One might argue that impossible events happen all the time and we're unable to detect them. In such a world, if K.C. suddenly ceased to exist, it would be impossible for us to notice that anything had changed. That's the dilemma of the multiple worlds theory: it's not only impossible to disprove, it's impossible to know if we're already in one. It's an unknowable unknowable. Rumsfeld would be proud.
sep 03 2020, 5:13 am
