Donald Hoffman

I think that's the case, but it's not a central point.

The fact is that many won't halt.

And so the question that Turing raised was something like this.

So is there a Turing machine that can tell you if it says, given this Turing machine and all these inputs, whether this Turing machine, which one of these inputs will it halt?

Okay.

And it turns out that there's no Turing machine that can do that.

So it's not a computable function.

There's no Turing machine that can tell you that whether this other Turing machine will halt or not on all these inputs.

Interesting.

So it can never understand it without running the calculation itself?

Well, and the Turing machine itself would never halt.

The one that was trying to do this would never halt.

Okay.

It's called the halting problem.

When you take a computer science class, you'll get a much better explanation than I've just given you.

Basically, you'll see that there's no algorithm that will tell you whether a particular Turing machine will halt or not on any possible inputs.

Well, first I'll just say I think a concrete example of the persistence is like I look up at the moon and then I look away.

And I say, is the moon still there?

And you look up and you say, oh, yeah, the moon is still there.

And then you look away and I look.