It would be an error, in view of the biological generalization proceeded on and the facts noted in this inquiry, to suppose that even in the Dark Ages, so called,1 the spirit of critical reason was wholly absent from the life of Christendom. It had simply grown very rare, and was the more discountenanced where it strove to speak. But the most systematic suppression of heresies could not secure that no private heresy should remain. As Voltaire has remarked, there was “nearly always a small flock separated from the great.”2 Apart too from such quasi-rationalism as was involved in semi-Pelagianism,3 critical heresy chronically arose even in the Byzantine provinces, which by the curtailment of the Empire had been left the most homogeneous and therefore the most manageable of the Christian States. It is necessary to note those survivals of partial freethinking, when we would trace the rise of modern thought.