True science teaches, above all, to doubt and be ignorant.
[La verdadera ciencia enseña, por encima de todo, a dudar y a ser ignorante.]
Miguel de Unamuno (1864-1936) Spanish philosopher and writer [Miguel de Unamuno y Jugo]
The Tragic Sense of Life [Del Sentimiento Trágico de la Vida], ch. 5 “The Rationalist Dissolution” (1913) [tr. Flitch (1921)]
Full text.