Whenever he thought about it, he felt terrible. And so, at last, he came to a fateful decision. He decided not to think about it. ~John-Roger and Peter McWilliams
Question #89701 posted on 05/15/2017 12:14 a.m.
Q:

Dear 100 Hour Board,

I have recently been introduced by a friend to the 100-Hour Board, and have become (stop me if you've heard this one before) a hopeless addict! I'm in the 2004 archives right now . . . just 13 more years . . .

Anyway, I've been pondering the Heisenberg uncertainty principle for a while, and wanted to ask the Board whether they think God's omniscience extends to knowing both the position and momentum of a particle at any moment. My initial thought is yes, God knows everything, so he necessarily would know that information and be able to cut through the uncertainty. However, from my understanding, such omniscience would overthrow the whole structure of the universe as we know it. Then again, omniscience of any kind would overthrow our telestial physics.

But being omniscient, the board members must know all about transcending mere science, right? At any rate I am interested to hear your responses; I am no scientist, so I'm happy to take some correction if my understanding of quantum physics is a little faulty!

-One-Winged Angle

A:

Dear you,

I would argue that even God cannot know both the position and momentum of a particle exactly. Let me explain.

The Heisenberg uncertainty principle comes from the principle that all matter is also a wave. The wavelength of an object is inversely proportional to the object's momentum. That means that a person walking around with a lot of momentum has an extremely small wavelength, so small in fact that it hardly matters. That's why you don't diffract through doors or have any other apparent wave-like behavior. But something with very little mass, like an electron for example, can have a big enough wavelength to act like a wave in ways that count.

So imagine a particle. It's also a wave. If we look at the wave, that wave extends forever in both directions, repeating over and over again with a certain wavelength. We know the wavelength, so we know the particle's momentum exactly. But since the wave extends infinitely through space, we have absolutely zero idea where the particle is. Now, if you combine a bunch of waves of slightly different wavelengths, you can get them to combine in a way that's localized, so that you know where the particle is to a certain degree. However, now the particle has many different momentums in a spread, so you don't know what the momentum is exactly anymore.

In short, you cannot know exactly the position and momentum of a particle because everything is a wave. The only way for that wave to have an exact momentum is for it to extend infinitely in either direction. It's not that there are facts that God doesn't know. God is omniscient. But some things aren't exact by their very nature, even with the perfect measurement. It's not a problem with measurement, it's a problem with the particle itself. Quantum physics makes the world weird like this, not because it's spooky or anything, but because everything is a wave, and waves have a certain vagueness to them.

This website has a bit more information (and pictures!) that could help.

Anyway, people used to believe that if you knew the current position and momentum of every particle in the universe with enough precision, you could perfectly predict what would happen for all of time. This posed a problem for the concept of agency. Is everything you do is simply the result of a complex machine (namely the universe) doing its thing? Where's the choice in that?

However, it's impossible for anyone to know that much about the universe because the universe, by it's own nature, is too vague. Every particle has a spread of both momentum and position rather than having exact values. We can figure out that spread, but there's a limit to how small that spread can be. So there's no way for the universe to be completely deterministic. And thus quantum physics has enabled the agency of man.

Additionally, the second law of thermodynamics states that entropy is always increasing. The universe is getting more and more disorganized. Disorder, or entropy, is another word for information. (Think of a TV screen. If the screen is all one color, you have maximum order and minimum information. If it's showing static, you have minimum order and maximum information. Neither is all that interesting to us, and it's in the spectrum between order and information where we find meaning.) If the total amount of information in the universe is always increasing, then a perfect knowledge of how everything was in the past could not lead to a perfect knowledge of the future, since any instant in the future holds more information than the past does. This additional information is created by the individual decisions that quantum particles are making all the time, deciding how their wavefunctions collapse and where they'll be. I'm not sure how, but God makes it possible for us to make decisions in a universe controlled by physics because decisions are being made all the time on the quantum level.

Einstein famously said, "God does not play dice." But he was wrong. We've shown over and over again that that's how the universe works at the most fundamental levels. And because we don't live in a fully deterministic universe, choice is made possible. God made the universe vague and weird just so we could have agency.

These are all my personal opinions, but hopefully you find them somewhat enlightening.

-Kirito