What made David realize, for the first time, that he wanted to live?

When the ship approaches its Italian harbor, the sailor who discovered David's presence onboard gives him a life preserver and helps him overboard. David makes his way to shore and then to the outskirts of the city where he lands. He then climbs to the top of the mountain where he is moved to tears by the colors he sees (see "Quotes", p. 27-28). Narration comments that "now he had learned about beauty he wanted to live ..."