That’s it. There is no other line that better encapsulates the sense of mortality, the impermanence of existence, the full realization that the world belongs to none of us any more than the other. There are thousands of songs, poems, novels, and movies about the subject. Religions exist to address such concerns. But nothing else needs to be said, there is no other knowledge that you need other than Louis Armstrong singing these simple lines. Because no other knowledge about out mortality exists. We were born, we went to school, perhaps we had kids of our own, we watch them grow, we say good bye to our elders, we die, and life goes on, the cycle continues. And what a wonderful world.