Andrew Gallimore

Now, interesting, have you ever, when you are dreaming,

So let's think about dreaming for a second.

It's quite instructive, I think.

When you're dreaming, right, the brain is actually constructing the world in basically the same way as it does when you're awake.

Dreams are kind of selective simulations of the waking world.

The difference, of course, is that there's no sensory inputs.

So if you scan someone's brain while they're having a dream, you'll see that this

back of the brain.

This primary visual cortex is kind of quiet.

The brain is kind of using what it's learned about building the world in the normal waking state to construct the dream world.

So the dream world is...

It's built from exactly the same stuff as the normal waking world.

However, there's interesting features.

In a dream, have you ever tried to use your cell phone?

No.

Not many people have.

But now there's actually a simpler way of that kind of reality tests.

A simpler way now is to get out your cell phone occasionally, open up the calculator and do a few calculations and just check everything's working, right?

Or open up a book.

And try to read it because the thing about the dream world is, again, just like the normal waking world, it's constructed over kind of levels of a hierarchy from the highest level models.