The Different Types of Heresy

Mode of Expression

  1. Internal (heresy remains in heretic’s mind, no external sign)
  2. External (manifested by external signs, such as words, deeds, omissions, even if no one sees them).

How Many People Heard or Saw

  1. Occult (heresy manifested to no one, or to just a few).
  2. Public (heresy openly and externally manifested before many).


Merkelbach, Summa Theo. Moral. 1. 743