“Custom is not truth; a practice is to be judged by reason and scripture, not by its antiquity.”
— Ram Mohan Roy[commonly attributed] Summary of Roy's method in controversies with orthodox opponents; wording not verified

Commentary

This maxim captures the method that Ram Mohan Roy applied in his controversies with orthodox Hindu leaders and with Christian missionaries alike: to test claims by appeal to reason and to the authentic scriptures rather than to tradition alone. The method placed him in a distinctive position, since he regarded himself as a defender of the true tradition against its corruptions. Sophia Dobson Collet's biography describes the public disputes in which he defended his views through printed pamphlets and essays. David Kopf, in The Brahmo Samaj and the Shaping of the Modern Indian Mind (1979), argues that Roy's critical use of scripture was among the most important features of modern Indian religious reform. The maxim is a summary of his polemical method, and the original pamphlets should be consulted for the exact arguments.