Up and down, front and back, left to right.

But appearances can be deceptive.

Many physicists now believe that reality is not, in fact, three-dimensional.

Instead they think that the fundamental core of reality

comes written in two-dimensional sheets, like this piece of paper.

In this view our world is a three dimensional projection

of information that's written on a two-dimensional surface,

an ilusion much like a hologram.

Clearly, this is insane.

What are these sheets?

Why would anyone think that reality is two-dimensional

when everything we know appears in 3 dimensions?

The answer lies in black holes.

Black holes famously suck in everything around them and never let go.

But what would happen if you were to throw something

with a lot of information into a black hole?

Something like a book or a hard drive.

Physicist know that information can never be lost, only scrambled.

So the information in our book can´t disappear forever

into the black hole, never to be recovered.

It must still exist somewhere accesible to us.

Physicists say it´s written on the so called event horizon of a black hole.

The two-dimensional surface that defines a point of no return.

Likewise, physicists have proven that events occurring on a two-dimensional sheet

are interchangeable with the description in three dimensions.

Mathematically it's all the same. Which leaves us to wonder:

Which is real? The three dimensions we observe

or the two dimensional description that makes the math work?

For Scientific American's Instant Egghead, I'm Michael Moyer.

Is is possible for an electron to be in two places at once?

Or for a cat to be both alive and dead at the same time?

According to quantum mechanics, both scenarios are possible.

And at the heart of this conceptual dilemma lies the wave function.