Dead/alive is often given as an example of complementary (or contradictory) antonymy. That's when if X is true, Y must be false and vice versa. If Lincoln is dead, then Lincoln is not alive. If Lincoln is alive, then Lincoln is not dead. Complementaries have no middle ground. You either are or you aren't.
But try to use
dead/alive as an example in a classroom or a textbook, and someone will say "what about vampires?" For them, we have the category of the
undead. Is
dead the opposite of
undead? Or is
alive? (I'll always answer such questions with 'depends on the context'.)
The supernatural aside, a complementary antonym pair is only complementary in the semantic domains to which they apply. My sofa is not alive, but that doesn't mean it's dead. Something has to have been alive to be dead, so the semantic domain for
dead/alive (and even
undead) is 'living things'.
Not or the prefix
non- put things in contradictory (or complementary) relations to one another regardless of the semantic domain.
What
xkcd gives us in this comic is
alive/not-alive. But although there's a firm line between the two, it treats both as gradable states, where prions and viruses are not alive, but rocks are
really not alive. The upward scale seems to be based on animacy and perhaps similarity to humans, while the downward scale mixes up criteria a bit more. I'm not entirely sure that I consider a prion to less not-alive than a rock with a face. In terms of things I'm likely to worship, the rock with a face comes higher, and surely I'm more likely to worship the less not-alive?
Anyway, it's funny. Thanks, xkcd.
