It is, then, by the union of knowledge and virtue that the soul frees itself from the world of darkness. As we know more and more of the nature of things, we are brought closer and closer to the world of light; and the love of that world becomes more and more intense. The stages of spiritual development are infinite, since the degrees of love are infinite. The principal stages, however, are as follows:—
(1). The stage of "I". In this stage the feeling of personality is most predominant, and the spring of human action is generally selfishness.
(2). The stage of "Thou art not". Complete absorption in one's own deep self to the entire forgetfulness of everything external.
(3). The stage of "I am not". This stage is the necessary result of the second.
(4). The stage of "Thou art". The absolute negation of "I", and the affirmation of "Thou", which means complete resignation to the will of God.
(5). The stage of "I am not; and thou art not". The complete negation of both the terms of thought—the state of cosmic consciousness.
Each stage is marked by more or less intense illuminations, which are accompanied by some indescribable sounds. Death does not put an end to the spiritual progress of the soul. The individual souls, after death, are not unified into one soul, but continue different from each other in proportion to the illumination they received during their companionship with physical organisms. The Philosopher of illumination anticipates Leibniz's doctrine of the Identity of Indiscernibles, and holds that no two souls can be completely similar to each other.[147:1] When the material machinery which it adopts for the purpose of acquiring gradual illumination, is exhausted, the soul probably takes up another body determined by the experiences of the previous life; and rises higher and higher in the different spheres of being, adopting forms peculiar to those spheres, until it reaches its destination—the state of absolute negation. Some souls probably come back to this world in order to make up their deficiencies.[147:2] The doctrine of trans-migration cannot be proved or disproved from a purely logical standpoint; though it is a probable hypothesis to account for the future destiny of the soul. All souls are thus constantly journeying towards their common source, which calls back the whole Universe when this journey is over, and starts another cycle of being to reproduce, in almost all respects, the history of the preceding cycles.
Such is the philosophy of the great Persian martyr. He is, properly speaking, the first Persian systematiser who recognises the elements of truth in all the aspects of Persian speculation, and skilfully synthesises them in his own system. He is a pantheist in so far as he defines God as the sum total of all sensible and ideal existence.[148:1] To him, unlike some of his Ṣūfī predecessors, the world is something real, and the human soul a distinct individuality. With the orthodox theologian, he maintains that the ultimate cause of every phenomenon, is the absolute light whose illumination forms the very essence of the Universe. In his psychology he follows Avicenna, but his treatment of this branch of study is more systematic and more empirical. As an ethical philosopher, he is a follower of Aristotle whose doctrine of the mean he explains and illustrates with great thoroughness. Above all he modifies and transforms the traditional Neo-Platonism, into a thoroughly Persian system of thought which, not only approaches Plato, but also spiritualises the old Persian Dualism. No Persian thinker is more alive to the necessity of explaining all the aspects of objective existence in reference to his fundamental principles. He constantly appeals to experience, and endeavours to explain even the physical phenomena in the light of his theory of illumination. In his system objectivity, which was completely swallowed up by the exceedingly subjective character of extreme pantheism, claims its due again, and, having been subjected to a detailed examination, finds a comprehensive explanation. No wonder then that this acute thinker succeeded in founding a system of thought, which has always exercised the greatest fascination over minds—uniting speculation and emotion in perfect harmony. The narrow-mindedness of his contemporaries gave him the title of "Maqtūl" (the killed one), signifying that he was not to be regarded as "Shahīd" (Martyr); but succeeding generations of Ṣūfīs and philosophers have always given him the profoundest veneration.
I may here notice a less spiritual form of the Ishrāqī mode of thought. Nasafī[150:1] describes a phase of Ṣūfī thought which reverted to the old materialistic dualism of Mānī. The advocates of this view hold, that light and darkness are essential to each other. They are, in reality, two rivers which mix with each other like oil and milk,[150:2] out of which arises the diversity of things. The ideal of human action is freedom from the taint of darkness; and the freedom of light from darkness means the self-consciousness of light as light.