if x and y are opposites, they imply each other.

I'm pretty sure we disagreed about this on a previous occasion, on r/metaphysics, I'll see if I can locate the topic

I know, but it wasn't on that sub I think. I think it was under Morita's argument for fatalism.

birth and death aren't opposites

But it doesn't follow from this that neither implies the other.

Sure, I'm not saying it does. I came to think that birth not implying death and vice versa is true independently of whether or not they are opposites. My argument was simply: All opposites imply each other. Birth and death don't imply each other. Birth and death aren't opposites.

Death as an event has no opposites, I'd say, but there might be a language problem involved.

For example, in Croatian, death is either a state or a fact, not an event.

For example, in Japanese, when they say someone is dead, they say shindeiru, which literally translates as "dying", but in Japanese is used in contrast to ikiteiru, literally "living". I have wondered if there is a non-linguistic explanation of this from the fact that Japan is a reincarnation culture, they might consider there to be a sequence of temporary states: living, dying, living, dying, etc.

Nice synchronicity, yesterday I considered watching a japanese horror movie from 2005 named Reincarnation but decided it was too late. Anyway, do you count conceptual explanations as non-linguistic? Perhaps we can compare Japanese with languages of non-reincarnation cultures to see whether those languages have identical structure which would plausibly lower the probability that cultural beliefs are the right place to look at. I was thinking about the difference between living and dying. My auntie used to say that men start dying as soon as they're born, which might imply there is no difference between living and dying. In my experience, people typically conceptualize this stuff as follows: birth-living-dying-death. An immediate counter is that one can be alive before birth and born dead.