markfiend

Heisenberg's Uncertainty Principle states that for any particle, the uncertainty of its position Δx and the uncertainty of its momentum Δp are such that:


So if a particle's momentum is known exactly, the uncertainty of its momentum is 0, then it could quite literally be anywhere in the universe; similarly if its position is known exactly, then its momentum could be any value from 0 to infinity.

This uncertainty would appear to be a logical necessity of the way the universe works at a quantum level; providing severe problems for omniscience. It is logically impossible to know everything.

So which set of "things" does an omniscient God know? Does He know the position of all things exactly, but not their momentums (momenta?)? Or does He know the momentum of all things exactly, but not their positions? Or does He have some uncertainty in both momentum and position?

Does this mean that theists must retreat from "Omniscience is knowledge of all things" to "Omniscience is uncertainty in all things"?

spacer1

Hi Mark, interesting topic.

I think that an omniscient God would not face the problem of HUP if you assume such a God exists outside of space and time. However, to even say this much presupposes that omniscience does not mean "total knowledge". One having total knowledge would know the true nature of the universe.

Additionally, I see HUP as being more a limitation of our own knowledge, rather than being a description of matter at the quantum level.

HRG

Beg to differ. HUP is not just a limitation of our knowledge: it can be deduced from a formula which is as basic to quantum mechanics as G m1 m2/r^2 is to Newtonian gravity (and as well tested experimentally) - the commutator between x (position) and p (momentum):

xp - px = -ih/2pi.

In a general state, neither x nor p have any sharp value; thus even an omnipotent deity could not "know" the value of x.

Regards,
HRG, Physicist (retd.)

Spenser

Gee Mark, my head just exploded.

I would love to see a theist (attempt to) escape this one...

Stephen T-B

Where did this idea of "omniscience" come from anyway?

I suggest, people whose knowledge, in respect of almost everything, was non-existent to fairly small.

Easy to say your god is "omniscient" if you're not having to consider Heisenberg's Uncertainty Principle.

Normal

So you're saying an omnipotent being could not design the world so that he knew the future but the world's inhabitants could not?

Jamie_L

I don't know. It seems like HUD is an attempt to put a physical situation into a mathematical form that isn't completely suited. We are not actually dealing with particles in the classical sense. We are dealing with quantum entities. The "knowledge" in question here isn't really a knowable quantity.

I would say omniscience entails knowing all that can be known. Can an omnipotent being know the locations of all living unicorns if there are no such things as living unicorns? If God doesn't know the locations of all these non-existant unicorns, does that mean God is not omnicient? Of course not.

Likewise, if there is effectively no such thing as a particle with x and p both sharply defined, then it is silly to say an omnipotent being should be able to know x and p for that particle. Not knowing this is no more a knock against his omniscience than it is that he doesn't know where the unicorns live.

Jamie

Spenser

That's just it. Quantities are knowable, neither is a square circle or an unmarried bachelor. Omniscience, by its more liberal definition, is knowing all things knowable. Both position and momentum are knowable, just not at the same time. So which does he know or to what extent of each. Putting degrees of his knowledge on one or the other seriously challenges the notion of omniscience...

Philosoft

Don't Bose-Einstein condensates depend upon the validity of the HUP for their mere existence?

Jamie_L

There seems to be a grammar error here. I'm not quite sure what you are saying.

An omnisicent being would know exactly what the position would be if you measured it under any given conditions. Likewise, an omnisicent being would know what the momentum would be if measured under any given conditions. The omniscient being would even be able to tell you both what the momentum would be and what the position would be if each were measured at time t. That is, if you measured momentum at 3:54:47 am, it would be p, but if instead you measured position at 3:54:47, it would b x.

Again, there it is meaningless to talk about knowing what both the momentum and position are simultaneously at time t, because those two quantities do not exist as distinct quantities simultaneously at time t.

Again, is it a knock against omniscience if an omniscient being can't tell us the exact location of non-existent unicorns?

Jamie