ELISHA BEN ABUYAH

Elisha ben Abuyah, a talmudic scholar from second century C.E., was excommunicated for heresy. It is said that four men entered Pardes. Ben Azzai died, Ben Zoma lost his mind, Rabbi Akiva entered whole and left whole, and Acher (Elisha ben Abuyah) cut the shoots (became heretical).
His disciple Rabbi Meir remained loyal to Elisha and is honored as a sage. Which says much. Meir digested the content of his teaching, but discarded the shell

It is said of Elisha that in consequence of his mother smelling the roasting meat of an idolatrous sacrifice he became a heretic. Yet Rabbi Yochanan’s mother even ate such meat – and Rabbi Yochanan was a righteous man.
It is written that events he witnessed lead him to question the concept of divine reward – evenso, he is counted among the righteous, because of the Torah that he learned and taught.