How technology has changed the definition of death

It’s surprisingly hard to say when things truly end.

Science teaches us a lot about the world, but sometimes it gives us more questions than answers. Our understanding of the natural world is filled with estimates, guesses, and predictions based on a shifting landscape of technology used to measure what's around us. And as technology has changed, the definition of "death" has shifted over the centuries.

In the 19th century, the moment one stopped breathing was the final indication of death, and a mirror held to the mouth, unfogged, was the indication that the soul had exited the body. Currently the measurement of death is a much more complicated one that involves a more industrialized and less religious view of the body: When mechanical and electrical activity ceases (the brain stops signaling, the heart stops beating, and breath stops), one is pronounced dead.

But as we peer into the body with more powerful tools, these markers of death might not really indicate a final end.

How did we get from there to here? Our video explains — and contemplates — the ever-changing answer.