The Long L

Lukáš Likavčan's title concept, taken from L in Frank Drake's 1961 equation for the number of detectable civilizations: how long a technological species stays around. Likavčan treats L not as a value to estimate but as a bridge from SETI back to Earth, since a civilization endures only by keeping its planet habitable, and in section 7 as a qualitative threshold: the technosphere's metabolism becomes isomorphic with the biosphere's, so a long-lived species' technosignatures are indistinguishable from biosignatures and it "hides in plain sight". Its parts are Metabolic Alignment (the index), Substrate-Agnostic Ecology (the theory of layers), and Assisted Reproduction / Assisted Evolution (the practice); habitability, following Chakrabarty, replaces sustainability as the norm. It resonates with Bratton's Viable Planetarity and Paradox of Intelligence, but where Bratton asks whether intelligence is self-extinguishing, Likavčan reads the Fermi silence as evidence that expansionist civilizations burn out and survivors are indistinguishable from nature.