Doubt is an element of criticism, and the tendency of criticism is necessarily skeptical.
Benjamin Disraeli (Earl of Beaconsfield) (1864). “Church policy: a speech delivered by the Right Hon. B. Disraeli, M.P. at a meeting of the Oxford Diocesan Society for the Augmentation of Small Livings, in the Sheldonian Theatre, Oxford, Nov. 25, 1864, etc”, p.17