Life and death appeared to me ideal bounds, which I should first break through, and pour a torrent of light into our dark world. Explain.

This sentence is claiming that life and death, as omnipresent as they may be in any form of existential reflection, are nothing but abstract notions that need to be somehow reevaluated in order to ascertain some sort of palliative for this unfathomable and often incomprehensible existence that we are gifted with, albeit not knowing its purpose or its reason.