2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/3189The affirmative statement of the existence of extraterrestrial life is tentatively raised to the status of a principle. Accordingly, Fermi's question is answered and the anthropic principle is shown to be falsifiable. The time-scale for the development of life on Earth and the age of the universe are the fundamental quantities upon which the arguments are framed.4 pages, also at http://www.fisica.ufmg.br/~dsoares/peel/peel_e.htmlAstrophysicstext