If you're reading this, you know what living looks like - movement, neurological activity, thought, action.
But what exactly is death?
The answer is complicated, suggests neuroscientist Christof Koch. In "Is Death Reversible?" a feature article in the most recent issue of Scientific American, Koch grapples with a death definition that is much more nuanced than you might think.
"Death, this looming presence just over the horizon, is quite ill defined from both a scientific as well as a medical point of view," he writes.
Koch tracks a shifting concept of death, from the cessation of breathing to the end of brain activity. And, he suggests, the modern medical definition is being shaken by new scientific developments.
"What at the beginning of the 20th century was irreversible - cessation of breathing - became reversible by the end of the century. Is it too difficult to contemplate that the same may be true for brain death? A recent experiment suggests this idea is not just a wild imagining."
Koch is referring to a series of surprising experiments in which scientists managed to restore some function in the brains of pigs that had been dead for hours. The research, which was published this April in the journal Nature, sparked intense ethical and scientific debate. It seems to point to death as a process, not an event, and raises the possibility that one day, scientists will be able to completely revive a dead brain.
If you think the research sounds Frankenstein-like, you're not alone. Even the scientists who conducted the experiments grappled with the ethical conundrum it presented, and had a plan B in which they'd stop the experiment immediately if the brains presented evidence of consciousness. Luckily for them, they didn't - but that could change one day as research progresses.
Koch grapples with that ethical conundrum, and the freaky realities of what our bodies can do even when our brains aren't online. The article isn't horror movie fodder or Halloween-themed . . . but it's well-timed if you're in the mood for some seriously chilling science.