Make your interests gradually wider and more impersonal, until bit by bit the walls of the ego recede, and your life becomes increasingly merged in the universal life. An individual human existence should be like a river — small at first, narrowly contained within its banks, and rushing passionately past rocks and over waterfalls. Gradually the river grows wider, the banks recede, the waters flow more quietly, and in the end, without any visible break, they become merged in the sea, and painlessly lose their individual being.
I would only expand by adding that there are many ways to merge with the sea, and not all follow this description exactly — but damn, that's good. As a human metaphor, as spiritual wisdom, that's 100% gold. So glad we gave that dude a Nobel Prize. :D