On being alive in the narrow sense
“We can only be said to be alive in those moments when our hearts are conscious of our treasures.”
Wilder puts a hard condition on the word alive. Breathing does not qualify; the sentence counts only the moments when you are aware of what you would hate to lose.
The severity is the interesting part. By this measure most of a life does not count, which sounds bleak until you notice it is a claim about attention rather than about circumstances. The treasures are not in question. Whether anyone is noticing them is.