There is an ecstasy that marks the summit of life, and beyond which life cannot rise. And such is the paradox of living, this ecstasy comes when one is most alive, and it comes as a complete forgetfulness that one is alive.

The speaker describes a peak state of experience—an “ecstasy” that represents life at its highest intensity. The paradox is that this apex arrives not through self-conscious reflection (“I am alive”) but through absorption so complete that the self disappears. London often dramatizes moments when extreme exertion, danger, or elemental contact with nature strips away social identity and interior chatter, leaving pure sensation and will. Read this way, the line suggests that the fullest vitality is not a thought about living but an unmediated immersion in it: the more intensely one lives, the less one stands apart to observe oneself living.