Can God change His mind?

Yesterday I wrote a bit about omniscience and choice. Today I want to plow a little deeper into a question on which I have no settled opinion: can God change His mind?

This thought occurred to me when reading 3 Nephi 17 a few days ago. I’ve read the passage uncounted times before and thought I had the story down: Christ says “‍I’m out; see you tomorrow.‍” The people give Him puppy-dog eyes. He relents and says “‍Okay, okay, I’ll stay a bit longer.‍” But as I read it I realized that, while that’s one valid reading, another is that He says instead “‍you need time to think this over before we go on so I’ll be leaving til tomorrow, but before I go…‍” In other words, I was left unable to tell if chapters 17 and 18 were in the original plan or not.

Can you be omniscient and change your mind? “‍I plan to do X, but at 12:43 tomorrow I’ll decide to do Y instead.‍” It just doesn’t make sense. The only way I can figure an omniscient being changing a decision is if either there are some things unknowable or if the omniscience is on demand rather than continual information.

Now, quantum physics tells us some things are unknowable. This is a combination of the oft-cited Heisenberg Uncertainty Principle, which says that some questions don’t make sense given what actually exists, and the specially defined-to-be-unknowable sense of “‍random‍” that comes out of wave function collapse. That some questions are the wrong questions I completely buy. waves can’t have location and heaps can’t have frequency so asking for the location and frequency of a waveform is nonsense. I’m not so sold on the defined-to-be-unknowable sense of “‍random‍”. I expect it will be discredited eventually, though I could be wrong.

If there are unknowable things—quantum, choice, or otherwise—what does omniscient mean? I suppose “‍knowing all things that are knowable;‍” and, assuming that the unknowable becomes knowable as time passes then God’s mind changing makes perfect sense.

But are there unknowable things?

I simply don’t know.