122. Division of Medieval Philosophy. -- Philosophy during the Middle Ages developed simultaneously in the West, at Byzantium and at various centres in the East; but of these three philosophies, Western, Byzantine and Eastern, the first is by far the most important. And in Western philosophy the main current of ideas is represented by scholasticism. We may therefore frame our divisions of medieval philosophy a potiori, according to the development of scholasticism.

From this point of view the scientific renaissance of the thirteenth century marks an epoch; the period that led up to it was a period of long and laborious elaboration: in the thirteenth century scholasticism unfolded all the rich resources of its peculiar genius; but the splendour of its triumphant reign was of short duration. Signs of its decadence appeared in the fourteenth century and multiplied in the fifteenth. From the middle of the fifteenth down to the seventeenth century, scholasticism languished, assaulted on all sides by the new systems that prepared the way for modern philosophy. It was in vain that a few distinguished men attempted in the sixteenth century to reinstate the dethroned sovereign: their influence was but local and ephemeral compared with that of the glorious past towards which they turned in vain.

Thus, we distinguish four periods in medieval philosophy

The first, or Period of Formation (from the ninth to the end of the twelfth century);

The second, or Period of Culmination (thirteenth century);

The third, or Period of Decline (fourteenth and first half of fifteenth century);

The fourth, or Period of Transition from medieval to modern philosophy (fifteenth to seventeenth century).

We will deal with the history of Byzantine and Eastern thought in the sections devoted to the various divisions of Western philosophy. During the first period each of the three currents developed in absolute independence of the others. Paris, Byzantium and Bagdad were the three great isolated centres of philosophical thought: to each of these a separate section will be devoted. But from the early years of the thirteenth century the separate currents united: Western philosophy drew a new and lasting vitality from the assimilation of Arabian and Byzantine ideas; while on the contrary the Jewish-Arabian philosophy quickly disappeared, and the Byzantine only languished down to the time of its total extinction in the fifteenth century. In the last three periods, accordingly, it will be sufficient to deal incidentally with the Byzantine, Arabian and Jewish philosophies, without devoting special sections to them.

Finally, there is no need of a geographical classification of Western philosophy, seeing that philosophy was no less international than the general scientific culture and civilization of the Middle Ages.