nature, easily receptive of a
clerical impression. The whole accumulated store of the lay learning of
the ages--geometry, astronomy, and natural science; grammar and
rhetoric; logic and metaphysics--this was the matter to be moulded and
the stuff to be permeated; and on this stuff St. Thomas wrought the
greatest miracle of genuine alchemy which is anywhere to be found in the
annals of learning.

The learning which the Church had to transform was essentially the
learning of the Hellenic world. Created by the centuries of nimble and
inventive thought which lie between the time of Thales and that of
Hipparchus, this learning had been systematized into a _corpus
scientiae_ during that age of Greek scholasticism which generally goes
by the name of Hellenistic. In its systematized Hellenistic form, it had
been received by the Roman world, and had become the culture of the
Roman Empire. By writers ranging from Ptolemy to Boethius the body of
all known knowledge had been arranged in a digest or series of pandects;
and along with the legal codification of Justinian it had been handed to
the Christian Church as the heritage of the ancient world. The attitude
of the Church to that heritage was for long unfixed and uncertain. The
logic, and still more the metaphysics, of Aristotle were not the most
comfortable of neighbours to the new body of Christian revelation
committed to the Church's keeping. In the hand of Berengar of Tours the
methods of Greek logic proved a corrosive to the received doctrine of
the Mass. In the hands of Abelard, in the _Sic et Non_, they served to
suggest the need of criticism of the text of Christian tradition. If
unity was to be preserved, a bridge must be built between the secular
science of the Greeks and the religious faith of the Church. In the
thirteenth century that bridge was built. Aristotle was reconciled with
St. Augustine; the _Organon_, the _Ethics_, and the _Politics_ were
incorporated in the body of Christian culture; and the mediaeval
instinct for unification celebrated its greatest and perhaps its most
arduous triumph.

The thirteenth century thus witnessed a unity of civilization alike as a
structure of life and as a content of the human mind. On the one hand,
there rose a single governing scheme of society, which culminated in the
universal primacy of Rome and the Roman pontiff. On the other hand, set
in this scheme, and contained in this structure, there was a single
stuff of thought