This is the Guardian.

It's Halloween. It's Halloween, so if you run into a ghost or a skeleton, you probably won't bat an eyelid.

After all, that's what Halloween's for, confronting the blurry line between the living and the dead.

But for my guest today exploring that murky

boundary is all in a day's work. When I say traverse the threshold of death I'm

talking biologically. Their hearts have stopped. They've been in this

limbo state between life and death and then we've brought them back to life again.

Sam Parnia is an associate professor of the New York University Grossman School of

Medicine.

He studies the science of death and resuscitation,

exploring what happens to us during cardiac arrest,

and what we remember if we make it back.

They become more lucid, and their thinking becomes sharper.

They describe a sense of a vast hyper-consciousness with incredible lucidity.

Near death. Incredible lucidity. Near-death experiences might still be viewed as pseudoscience by some,

but for Sam, they could hold the key to a better understanding of life, death and consciousness.

So is it time to radically alter our definition of death?

And how might medicine change if we do?

I'm the Guardian Science Editor Ian Sample,

and this is Science Weekly.

Well, got me interested of course is the fact that we deal with life and death on a daily basis. Alongside his academic roles Sam is also an intensive care doctor, and it was this work that got him thinking about the line between life and death.

I came across this even as a medical student, and I was intrigued that somehow medicine and science seemed to have

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