Miguel de Unamuno Doubt Quotations

The skeptic does not mean him who doubts, but him who investigates or researches, as opposed to him who asserts and thinks that he has found.

Life is doubt, and faith without doubt is nothing but death.

Faith which does not doubt is dead faith.

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

The supreme triumph of reason is to cast doubt upon its own validity.