Momentariness, but birth and death? If everything exists for an instant only, as with Sautrāntika Buddhism, then doesn't that mean everything dies at the exact same time it is born? Isn't that impossible?
I am not asking for an analysis of the sutta pitaka, but to understand how anyone could hold those two positions. Did it ever come up in historical debate?
I would say there were two ways of looking at this.

You can't exist &quot;for&quot; an instant but you can exist &quot;at&quot; this instant.
You are not living five minutes ago, or two hours in the future.
You are living at this precise moment.
&quot;You&quot; are living in this instant and this &quot;you&quot;
is different to the &quot;you&quot; of last week or last year or five mins ago.  As you experience things, you change and become a different person.  You don't die or become a different being.