Thus, then, it was only too possible for error to find its entrance even here also. And it is remarkable that both its principal forms, such as in varying shapes the history of philosophy is constantly presenting to us in the different epochs of its progress, here again most distinctly present themselves with all the features of their intellectual physiognomy plainly marked, and with the still more obvious contrast of their intrinsic diversity. A philosophy of nature more or less visionary and fanciful was the common basis of the various Gnostic sects. With their long series of imaginary emanations from the Deity, resembling in no slight degree the old heathen genealogies of the gods, they would, had they triumphed, have converted Christianity into a similar mythology, though of a more philosophical character. In the Arians, on the contrary, and other kindred sects before and after them, we recognize rather the spirit of rationalism, which, dwelling on some point of life, or theory, with a show of rigor and accuracy, while, apparently, it disputes only about words, is, in fact, undermining the foundation of the most essential ideas. All these parties, however, as they originated, so they also disappeared, within the first five or eight centuries of our era. It was, therefore, impossible for their pernicious influence to gain a deep hold of life. At least it was neither universal nor permanent. Yet by them the ardor of a first love was cooled. And sad, indeed, has been the loss as regards the fullness of living energy, and even in respect of profounder wisdom. The history of the middle ages again presents a rare and singular phenomenon. One great mind and writer of antiquity, whose influence in his own day was far from extensive, became at this date, in a most remarkable manner, the problem and center of scientific inquiry. For several centuries the human mind was laboriously engaged in disputing about the philosophy of Aristotle. And although men did not understand it--not, at least, its deeper meaning, for they lacked the first and most essential qualifications, and also the requisite means for such a purpose--this apparently aimless disputation, and this unsolved problem, was, nevertheless, not without great and manifold influence on their own and the following ages. It has had a permanent effect on the whole frame of man’s life and being. Of the two wholly different aspects which, as we have already so often remarked, the philosophy of Aristotle presents, it was probably not its fruits of rationalism (for, at this period, such were generally regarded as forbidden) that throughout the great part of the then civilized world excited so incredible a fondness for this all-absorbing and all-understanding system. Its attraction lay rather in some great and mysterious knowledge of nature. And the desire for these intellectual treasures was not a little heightened by the fact, that, in general, they were inaccessible.