I believe that it is in the question of schism rather than heresy that the key to the problem of the disunity of Christendom is to be found. For heresy as a rule is not the cause of schism but an excuse for it, or rather a rationalization of it. Behind every heresy lies some kind of social conflict, and it is only by the resolution of this conflict that unity can be restored.

— Christopher Dawson, The Judgment of the Nations (1942)