Heresiologists in general use Gnostikoi to indicate those people who belong to a hairesis or schole that deviates from their own Catholic form of Christianity. This pejorative keying of gnöstikoi with hairesis in a deviant sense is a strategic way that heresiologists mark the Gnostics negatively as outsiders and transgressers of Catholic Christianity. The Gnostics were understood by the heresiologists to be so diverse, that Irenaeus compares the Gnostics to mushrooms that have sprung up among the Christians.