Undoubtedly it is our duty, and for our best good, that we occupy and improve the faculties, with which our creator has endowed us, but so far as prejudice, or prepossession of opinion prevails over our minds, in the same proportion, reason is excluded from our theory or practice. Therefore if we would acquire useful knowledge, we must first divest ourselves of those impediments and sincerely endeavor to search out the truth: and draw our conclusions from reason and just argument, which will never conform to our inclination, interest or fancy but we must conform to that if we would judge rightly.

Ch. XIII Section II - Of The Importance of the Exercise of Reason, and Practice of Morality, in order to the Happiness of Mankind - Reason: The Only Oracle Of Man (1784)