As if or If?

Hello masters;

In this sentence:

As I understand it, for you philosophy and literature remind us that ‘not all of me will die’, or, rather, that it is not worth living as if everything depended on us.

1. I can't get the meaning of "as if" here? Can I say "if everything depended on us, then it is not worth living"? Or, "because everything depended on us, it is not worth living"?

2. What is the relationship between the two parts of sentence, I mean, "not all of me will die" and "that it is not worth living as if everything depended on us"?

Thank you for your help.