True science teaches, above all, to doubt and to be ignorant.

Unamuno frames “true science” not as a storehouse of final answers but as a disciplined attitude: skepticism, self-critique, and the willingness to admit ignorance. “To doubt” signals method—testing claims, resisting dogma, and keeping inquiry open. “To be ignorant” is not anti-intellectual; it is the honest recognition of limits, the starting point that prevents knowledge from hardening into ideology. The quote also carries an ethical edge typical of Unamuno: humility is a virtue, and certainty can become a form of spiritual or political arrogance. In this sense, science’s greatest lesson is not omniscience but intellectual conscience—knowing how much remains unknown.