Remember me affectionately to good Dr. Price and to the honest heretic Dr. Priestly. I do not call him honest by way of distinction; for I think all the heretics I have known have been virtuous men. They have the virtue of fortitude or they would not venture to own their heresy; and they cannot afford to be deficient in any of the other virtues, as that would give advantage to their many enemies; and they have not like orthodox sinners, such a number of friends to excuse or justify them. Do not, however mistake me. It is not to my good friend's heresy that I impute his honesty. On the contrary, 'tis his honesty that has brought upon him the character of heretic.

Letter to Benjamin Vaughan (24 October 1788) - Epistles