In The Princess Bride, the always sagacious Miracle Max—aka Billy Crystal—points out “there’s a big difference between mostly dead and all dead.” And he wasn’t wrong.
Death has always been something of a moving target. Take, for example, the first edition of the Encyclopedia Britannica, published in 1768, that defined the term as “the separation of soul and body; in which sense it stands opposed to life, which consists in the union thereof.
But how can you tell when said separation occurs? Well, that’s a slightly more complicated procedure and one we still haven’t quite cracked. Thus, moving forward, and trying for an—um— more practical definition, we began to define the end of life by a series of cessations.
In the beginning, breath was life. Of course, this idea led to the obvious reversal, the cessation of breath, meant the cessation of life. But that didn’t last for long.
As our knowledge of biology improved, death became definable by the cessation of heart function. In other words, if you were out of pulse, you were out of time.
But advances in neuroscience, ideas about brain death, and the introduction of mechanical ventilators—with their ability to keep the heart pumping long after the brain had died—forced a society-wide reevaluation of terms.