… an immense spectrum of complexity, from a single hydrogen atom to something as intricate as a brain. In trying to define life, we have drawn a line at an arbitrary level of complexity and declared that everything above that border is alive and everything below it is not.
(T)his division does not exist outside the mind.
There is no threshold at which a collection of atoms suddenly becomes alive, no categorical distinction between the living and inanimate, no Frankensteinian spark.
We have failed to define life because there was never anything to define in the first place.