It was far otherwise with the spirit of Abélard, the fundamental principle or maxim on which all else depended. The thirteenth century cordially accepted that principle, and applied itself to the rationalisation of theology. It wholly abandoned the mysticism of Bernard and the school of St. Victor. The Cistercian had summed up Abélard’s misdeeds thus in his letter to the pope: ‘He peers into the heavens and searches the hidden things of God, then, returning to us, he holds discourse on ineffable things of which a man may not speak.’ In the very sense in which this was said of Abélard, it may be urged as a chief characteristic of the saintly schoolmen of the thirteenth century. Even St. Bonaventure was no mystic in the anti-rational sense of Bernard; simply, he applied to theology the reason of Plato instead of the reason of Aristotle. Archbishop Roger Vaughan, in his _Life of St. Thomas_, says that the schoolmen owed the ‘_probatur ratione_’ in their _loci theologici_ to Abélard. That is already a most striking vindication of Abélard’s characteristic teaching as to the function of reason, for we know how important the ‘proofs from reason’ were in the scheme of Aquinas and Scotus. But they really owe far more than this to Abélard. If they have deserted the dreamy, rambling, fruitless, and fantastic speculation of the mystic school for a methodical and syllogistic inquiry concerning each point of faith, it is largely due to the example of Abélard. The schoolmen notoriously followed Peter the Lombard. From the _Sentences_ of Peter the Lombard to the _Sic et Non_ of Peter Abélard—through such works as the _Sentences_ of Roland and Omnebene of Bologna and the so-called _Sentences of Peter Abélard_—is a short and easy journey. No doubt we must not lose sight of that other event which so powerfully influenced the theology of the thirteenth century: the invasion of the Arab and Jew philosophers. Theirs is the only influence of which the schoolmen show any consciousness in their elaborate fortification of dogma to meet the criticism of reason and conscience—except for the avowed influence of the Lombard; and along that line we may trace the direct influence of Abélard.