In the age that follows the flowering of the Greek world conceptions, philosophy submerges into religious life. The philosophical trends vanish, so to speak, into the religious currents and emerge only later. It is not meant to imply by this statement that these religious movements have no connection with the development of the philosophical life. On the contrary, this connection exists in the most extensive measure. Here, however, no statement about the evolution of religious life is intended, but rather a characterization of the development of the world conceptions insofar as it results from thought experience as such.
After the exhaustion of Greek thought life, an age begins in the spiritual life of mankind in which the religious impulses become the driving forces of the intellectual world conceptions as well. For Plotinus, his own mystical experience was the source of inspiration of his ideas. A similar role for the spiritual development of mankind in its general life is played by the religious impulses in an age that begins with the exhaustion of Greek philosophy and lasts approximately until John Scotus Erigena (died 885 A.D.)
The development of thought does not completely cease in this age. We even witness the unfolding of magnificent and comprehensive thought structures. The thought energies, however, do not have their source within themselves but are derived from religious impulses.
The religious mode of conception in this period flows through the developing human souls and the resulting world pictures are derived from this stimulation. The thoughts that occur in this process are Greek thoughts that are still exerting their influence. They are adopted and transformed, but are not brought to new growth out of themselves. The world conceptions emerge out of the background of the religious life. What is alive in them is not self-unfolding thought, but the religious impulses that are striving to manifest themselves in the previously conquered thought forms.
We can study this development in several significant phenomena. We can see Platonic and older philosophies engaged on European soil in the endeavor to comprehend or to contradict what the religions spread as their doctrines. Important thinkers attempt to present the revelations of religion as fully justified before the forum of the old world conceptions.
What is historically known as Gnosticism develops in this way in a more Christian or a more pagan coloring. Personalities of significance of this movement are Valentinus, Basilides and Marcion. Their thought creation is a comprehensive conception of world evolution. Cognition, gnosis, when it rises from the intellectual to the trans-intellectual realm, leads into the conception of a higher world-creative entity. This being is infinitely superior to everything seen as the world by man, and so are the other lofty beings it produces out of itself — the aeons. They form a descending series of generations in such a way that a less perfect aeon always proceeds from a more perfect one. As such, in a later stage of evolution an aeon has to be considered to be also the creator of the world that is visible to man and to which man himself belongs. Into this world an aeon of the highest degree of perfection now can join. It is an aeon that has remained in a purely spiritual, perfect world and has there continued its development in the best possible way, while other aeons produced the imperfect and eventually the sensual world including man. In this manner, the connection of the two worlds that have gone through different paths of evolution is thinkable for the Gnostic. The imperfect world receives its stimulation at a certain point of evolution by the perfect one in order that it may begin to strive toward the perfect.
The Gnostics who were inclined toward Christianity saw in Christ Jesus the perfect aeon, which has united with the terrestrial world.
Personalities like Clemens of Alexandria (died ca. 211 A.D.) and Origen (born ca. 185 A.D.) stood more on a dogmatic Christian ground. Clemens accepts the Greek world conceptions as a preparation of the Christian revelation and uses them as instruments to express and defend the Christian impulses. Origen proceeds in a similar way.
We find a thought life inspired by religious impulses flowing together in a comprehensive stream of conceptions in the writings of Dionysius the Areopagite, which are mentioned from 533 A.D. on. They probably had not been composed much earlier, but they do go back, not in their details but in their characteristic features, to earlier thinking of this age. Their content can be sketched in the following way. When the soul liberates itself from everything that it can perceive and think as being, when it also transcends beyond what it is capable of thinking as non-being, then it can spiritually divine the realm of the over-being, the hidden Godhead. In this entity, primordial being is united with primordial goodness and primordial beauty. Starting from this primeval trinity, the soul witnesses a descending order of beings that lead down to man in hierarchical array.
In the ninth century Scotus Erigena adopts this conception of the world and develops it in his own way. The world for him presents itself as an evolution in four forms of nature. The first of these is the creating and not created nature. In it is contained the purely spiritual primordial cause of the world out of which evolves the creating and created nature. This is a sum of purely spiritual entities and energies, which through their activity produce the created and not creating nature, to which the sensual world and man belong. They develop in such a way that they are received into the not created and not creating nature, in which the facts of salvation, the religious means of grace, etc., unfold their effect.
In the world conceptions of the Gnostics, Dionysius and Scotus Erigena, the human soul feels its roots in a world ground on which it does not base its support through the forces of thought, but from which it wants to receive the world of thought as a gift. The soul does not feel secure in the native strength of thought. It strives, however, to experience its relation to the world ground in the form of thought. The soul has thought itself enlivened by another energy that derives from religious impulses, whereas in the Greek thinkers it lived out of its own strength. Thought in this age existed, so to speak, in a form in which its own energy was dormant. In the same way, we may also think of the energy of picture conception in the centuries that preceded the birth of thought. There must have been an ancient time when consciousness in the form of picture conception flourished, the same as did the later thought consciousness in Greece. It then drew its energy out of other impulses and only when it had gone through this intermediate state did it transform into thought experience. It is an intermediate state in the process of thought development that we witness in the first centuries of the Christian era.
In those parts of Asia where the conceptions of Aristotle had been spread, the tendency now arose to lend expression to the semitic religious impulses in the ideas of the Greek thinker. This tendency was then transplanted also to European soil and so entered into the European spiritual life through such thinkers as the great Aristotelians, Averroës (1126–1198), Maimonides (1135–1204), and others.
In Averroës, we find the view that it is an error to assume that a special thought world exists in the personality of man. There is only one homogeneous thought world in the divine primordial being. As light can be reflected in many mirrors, so also one thought world is revealed in many human beings. During human life on earth, to be sure, a further transformation of the thought world takes place, but this is, in reality, only a process in the spiritually homogeneous primordial ground. With man's death, the individual revelation through him simply comes to an end. His thought life now exists only in the one thought life.
This world conception allows the Greek thought experience to continue its effect, but does it in such a way that it is now anchored in the uniform divine world ground. It leaves us with the impression of being a manifestation of the fact that the developing human soul did not feel in itself the intrinsic energy of thought. It therefore projected this energy into an extra-human world power.