The improver of natural knowledge absolutely refuses to acknowledge authority, as such. For him, skepticism is the highest of duties, blind faith the one unpardonable sin.

Thomas Henry Huxley (1825–1895), Darwin’s most prominent Victorian defender, repeatedly argued that science advances by disciplined doubt rather than deference to tradition. The wording of this quotation reflects his broader campaign against appeals to “authority” in matters of natural knowledge—whether ecclesiastical, philosophical, or institutional—and his insistence that scientific claims must be tested by evidence and reasoned criticism. It fits the intellectual climate of mid-to-late 19th-century Britain, when debates over evolution, biblical criticism, and the professionalization of science made the boundaries between faith, authority, and empirical inquiry a public controversy.

Huxley contrasts two epistemic attitudes: the scientist’s obligation to doubt and verify versus the moralized acceptance of claims on mere authority. By calling skepticism a “duty,” he frames critical inquiry not as cynicism but as an ethical commitment to intellectual honesty and self-correction. “Blind faith” becomes the “unpardonable sin” because it halts investigation and shields beliefs from revision. The quote encapsulates Huxley’s view of science as a method—organized skepticism, evidential standards, and willingness to abandon cherished ideas—rather than a fixed body of doctrines. It also signals his broader secular stance: truth about nature should not be settled by prestige, tradition, or revelation.