The second type of mediæval heresy is that represented by Tanchelm, Eon de l’Etoile, Segarelli, Dolcino, the Flagellants. It belongs to the province, not of the theologian but of the psychologist, specially interested in the study of depraved emotion and diseased imagination. Its foundation is that perverted sexuality which is so strangely connected, as a matter of psychological fact, with intensity of religious enthusiasm. The cases of Tanchelm and Eon are no doubt cases of simple religious mania. None of the heresies of this type had, or from their character was at all likely to have, any but the most fleeting results. They have, nevertheless, their interest, as symptoms of the powerful emotionalism which seemed equally liable to produce a fierce animalism or an intense religious asceticism. The same raw material of unregenerate sense and passion gave to the Church saints and heresiarchs. Ever in the Middle Ages there was a tendency to excess, excess of self-abnegation, excess of self-indulgence, a tendency to push ideas both of doctrine and conduct to extremes. Thus did the Spiritual Franciscans tend to see in their founder a superman, to make the cult of poverty an obsession, to believe themselves a new order destined to inaugurate the era of the Holy Ghost. The third type of mediæval heresy is of an altogether different nature. It is intellectual, philosophic. In all the other heresies there is a taint of rottenness, disease. Here, on the other hand, there is the health and sanity of honest thinking—and though the thought be crude, obscure or exaggerated, there is at least the possibility of lasting results. In the re-discovery and re-absorption of the intellectual heritage of classical and patristic times there was always the danger of heresy. The process of adapting knowledge, pagan in source, coming sometimes through infidel channels, was certainly perilous. It has to be remembered that it was the Church that initiated and carried through this process; that to the Church the world is indebted for the Renaissance of the twelfth and thirteenth centuries. But the process inevitably presented serious problems. In the first place, it yielded a copious mass of new comment and interpretation upon the original body of Christian dogma, viewed from a philosophic standpoint. Apply the logical methods of scholasticism and envisage dogma in the light of the metaphysical problem of the relations between the universal and the particular, and you have to decide whether the realist, the nominalist or the conceptualist is the true interpreter of the creeds. The difficulty was increased with the advent of Aristotelianism in the thirteenth century. One exposition of Aristotle was definitely declared to be heresy—that of the Averrhoïsts. But the Augustinian opponents of St. Thomas Aquinas endeavoured to confound him in the charge of heresy: and it was for a time doubtful whether Aristotelianism in any shape or form could be accepted as orthodox.