I used the adjective "Pelagian" in yesterday's post. Pelagius was a monk from the British Isles, perhaps an Irish Celt, who tangled with Augustine in the 5th century, and was condemned by the Church as a heretic. He taught that the world was not corrupted by Adam's sin, and that humans can live good lives by the ordinary powers given them by nature. "Concupiscence" loomed large in Augustine's theology, and subsequently in Christian doctrine. Pelagius -- bless him -- had a more positive view of human nature, and of nature itself -- sufficient grounds for condemnation by an institution that claimed to alone possess the keys to salvation.
I was educated at a time when heresies loomed large in Catholic apologetics. I recall a little Handbook of Heresies by M. L. Cozens, published, of course, by Sheed & Ward, and which I have just found a battered copy of in the college library. Here they are, all the ways of being wrong, starting with the Judaic heresy and moving on through Gnosticism, Montanism, Sabellianism, Arianism, Semi-Arianism, Apollinarianism, Nestorianism, Eutychianism, Monothelitism, Pelagianism, and so forth, to Protestantism and Modernism. Some of these heresies turned on fine points of theological debate; thus the need of the Church's infallible magisterium to keep one on the straight and narrow
Some folks claim that science is a secular religion. Well, in all of my years of science-watching, I don't recall hearing the word "heresy" applied to an unorthodox scientific theory. If science is a religion, then there is only one established doctrine: that nature's laws can be known ever more reliably by the application of human reason and reproducible empirical observation. We treasure our rebels -- Galileo, Darwin, Einstein, Wegener -- but don't warmly welcome to the fold those who arrive forearmed with handbooks of heresies. Science seeks a balance between dogmatic certitude and intellectual anarchy. My way of putting it is this: Science must be radically open to marginal change and marginally open to radical change. Sometimes dissent can be a healthy step forward.