subjective experiences that many people have

when they come close to death

or sometimes when they are, in fact, pronounced dead.

And they include such difficult to explain phenomena as:

a sense of leaving the physical body,

reviewing one's entire life,

encountering some other entities

that aren't physically present that they sometimes interpret

as deities or deceased loved ones.

And at some point coming to a point of no return

beyond which they can't continue

and still come back to life.

It's natural for people to think that

near-death experiences are kind of like dreams

or hallucinations.

No two people have the same type of hallucination.

Whereas near-death experiences are basically the same

across people, across cultures, across centuries.

I think if you look at what things

typically cause hallucinations-

metabolic changes, drugs,

changes in oxygen level, brain injury,

those things produce certain known effects:

confusion, agitation, belligerence.

They're very different from the typical

calm, peaceful, consistent content

of a near-death experience.

We've looked at specific things that may cause

a hallucination.

It was thought that maybe lack of oxygen to the brain

would have a role in near-death experiences,

since no matter how you come close to death,

lack of oxygen to the brain is one of

the final, common pathways.

But those who report near-death experiences

actually have better oxygen flow to the brain

than people who don't report NDEs.

Likewise, we thought drugs given to people

as they approach death may be causing these experiences.

And what we find again is that

the more drugs people are given as they approach death,

the less likely they are to report a near-death experience.

So drugs and lack of oxygen are not causing NDEs.

They may in fact, repress having an NDE.

You can look on a dream as just a random series of visions;

a way of processing problems in your life,

and finding solutions.

There are phenomenological differences,

differences in the content between dreams

and near-death experiences.

Near-death experiences often have accurate

out of body perceptions,

whereas dreams and hallucinations do not.

And that to me is probably one of the best ways

of distinguishing between a dream

and a near-death experience.

Is there any connection between dreams

and near-death experiences?

The fact that both of those are processed

by our brains ultimately

says that there's got to be some similarities

in how we describe them, how we understand them,

how we relate them to other people.

Many near-death experiencers report things

that other people can't verify right away.

So we assume that they were just imagination or fantasy,

and yet they insist, "It's real.

It's happened to me.

I know it."

Philosopher Abraham Kaplan talks about

the story of a traveler who went to a distant land,

and came back with a fantastic story about a beast

who can travel for days and days and days without water.

And he tells this to his people in his town

and they get together and say

"We don't know if this can be real,

but we're gonna get the wise men together and have a meeting

and decide whether this beast can exist or not."

And the traveler says, "What do you mean can exist?

I saw it."

So it's like, if you were hit by a truck,

and someone says you just imagined it.

You know whether you're hit by a truck or not.

There's no doubt in your mind.

And that's the way near-death experiencers relate

to their NDE.

They feel like, 'There's no doubt in my mind,

this is a real experience I had.

More real than this world is.'