Every church pretends that it has a revelation from God, and that this revelation must be given to the people through the church; that the church acts through its priests, and that ordinary mortals must be content with a revelation — not from God — but from the church. Had the people submitted to this preposterous claim, of course there could have been but one church, and that church never could have advanced. It might have retrograded, because it is not necessary to think or investigate in order to forget. Without heresy there could have been no progress.
Heretics and Heresies (1874)