joy for the living is sorrow for the dead (5-6)
These lines speak the most specifically about life, consciousness, and existence than any other lines in the poem. Yet the thing is, depending on how you read them, they can be taken to carry many meanings. They can provide solace for sorrow, showing that yes, existence results in death, and death is sad, but only because of the joy we feel in life. So existence is only sad because it's joyful. We wouldn't be sad to die if we weren't happy to live. Yet the lines are arranged with the end note falling on sorrow, which could mean that the poem is a little more depressing—all joy must end in sorrow at the ceasing of that joy. But we'll be getting onto that more in the themes section about "Sadness."