More than twenty-five centuries have passed since that which has been called the Perennial Philosophy was first committed to writing; and in the course of those centuries it has found expression, now partial, now complete, now in this form, now in that, again and again. In Vedanta and Hebrew prophecy, in the Tao Te Ching and the Platonic dialogues, in the Gospel according to St. John and Mahayana theology, in Plotinus and the Areopagite, among the Persian Sufis and the Christian mystics of the Middle Ages and the Renaissance--the Perennial Philosophy has spoken almost all the languages of Asia and Europe and has made use of the terminology and traditions of every one of the higher religions. But under all this confusion of tongues and myths, of local histories and particularist doctrines, there remains a Highest Common Factor, which is the Perennial Philosophy in what may be called its chemically pure state. This final purity can never, of course, be expressed by any verbal statement of the philosophy, however undogmatic that statement may be, however deliberately syncretistic. The very fact that it is set down at a certain time by a certain writer, using this or that language, automatically imposes a certain sociological and personal bias on the doctrines so formulated. It is only the act of contemplation when words and even personality are transcended, that the pure state of the Perennial Philosophy can actually be known. The records left by those who have known it in this way make it abundantly clear that all of them, whether Hindu, Buddhist, Hebrew, Taoist, Christian, or Mohammedan, were attempting to describe the same essentially indescribable Fact.The original scriptures of most religions are poetical and unsystematic. Theology, which generally takes the form of a reasoned commentary on the parables and aphorisms of the scriptures, tends to make its appearance at a later stage of religious history. The Bhagavad-Gita occupies an intermediate position between scripture and theology; for it combines the poetical qualities of the first with the clear-cut methodicalness of the second. The book may be described, writes Ananda K. Coomaraswamy in his admirable Hinduism and Buddhism, “as a compendium of the whole Vedic doctrine to be found in the earlier Vedas, Brahmanas and Upanishads, and being therefore the basis of all the later developments, it can be regarded as the focus of all Indian religion” is also one of the clearest and most comprehensive summaries of the Perennial Philosophy ever to have been made. Hence its enduring value, not only for Indians, but for all mankind.At the core of the Perennial Philosophy we find four fundamental doctrines.First: the phenomenal world of matter and of individualized consciousness--the world of things and animals and men and even gods--is the manifestation of a Divine Ground within which all partial realities have their being, and apart from which they would be non-existent.Second: human beings are capable not merely of knowing about the Divine Ground by inference; they can also realize its existence by a direct intuition, superior to discursive reasoning. This immediate knowledge unites the knower with that which is known.Third: man possesses a double nature, a phenomenal ego and an eternal Self, which is the inner man, the spirit, the spark of divinity within the soul. It is possible for a man, if he so desires, to identify himself with the spirit and therefore with the Divine Ground, which is of the same or like nature with the spirit.Fourth: man’s life on earth has only one end and purpose: to identify himself with his eternal Self and so to come to unitive knowledge of the Divine Ground.In Hinduism the first of these four doctrines is stated in the most categorical terms. The Divine Ground is Brahman, whose creative, sustaining and transforming aspects are manifested the Hindu trinity. A hierarchy of manifestations connects inanimate matter with man, gods, High Gods, and the undifferentiated Godhead beyond.In Mahayana Buddhism the Divine Ground is called Mind or the Pure Light of the Void, the place of the High Gods is taken by the Dhyani-Buddhas.Similar conceptions are perfectly compatible with Christianity and have in fact been entertained, explicitly or implicitly, by many Catholic and Protestant mystics, when formulating a philosophy to fit facts observed by super-rational intuition. Thus, for Eckhart and Ruysbroeck, there is an Abyss of Godhead underlying the Trinity, just as Brahman underlies Brahma, Vishnu and Shiva. Suso has even left a diagrammatic picture of the relations subsisting between Godhead, triune God and creatures. In this very curious and interesting drawing a chain of manifestation connects the mysterious symbol of the Divine Ground with the three Persons of the Trinity, and the Trinity in turn is connected in a descending scale with angels and human beings. These last, as the drawing vividly shows, may make one of two choices. They can either live the life of the outer man, the life of the separative selfhood; in which case they are lost (for, in the words of the Theologia Germanica, “nothing burns in hell but the self”). Or else they can identify themselves with the inner man, in which case it becomes possible for them, as Suso shows, to ascend again, through unitive knowledge, to the Trinity and even, beyond they Trinity, to the ultimate Unity of the Divine Ground.Within the Mohammedan tradition such a rationalization of the immediate mystical experience would have been dangerously unorthodox. Nevertheless, one has the impression, while reading certain Sufi texts, that their authors did in fact conceive of al haqq, the Real, as being the Divine Ground or Unity of Allah, underlying the active and personal aspects of the Godhead.The second doctrine of the Perennial Philosophy--that it is possible to know the Divine Ground by a direct intuition higher than discursive reasoning--is to be found in all the great religions of the world. A philosopher who is content merely to know about the ultimate Reality--theoretically and by hearsay--is compared by Buddha to a herdsman of other men’s cows. Mohammed uses an even homelier barnyard metaphor. For him the philosopher who has not realized his metaphysics is just an ass bearing a load of books. Christian, Hindu, Taoist teachers wrote no less emphatically about the absurd pretensions of mere learning and analytic reasoning. In the words of the Anglican Prayer Book, our eternal life, now and hereafter, “stands in the knowledge of God”; and this knowledge is not discursive, but “of the heart,” a super-rational intuition, direct, synthetic and timeless.The third doctrine of the Perennial Philosophy, that which affirms the double nature of man, if fundamental in all the higher religions. The unitive knowledge of the Divine Ground has, as its necessary condition, self-abnegation and charity. Only by means of self-abnegation and charity can we clear away the evil, folly and ignorance which constitute the thing we call our personality and prevent us from becoming aware of the spark of divinity illuminating the inner man. but the spark within is akin to the Divine Ground. By identifying ourselves with the first we can come to unitive knowledge of the second. These empirical facts of the spiritual life have been variously rationalized in terms of the theologies of the various religions. The Hindus categorically affirm that thou art That--that the indwelling Atman is the same as Brahman. For orthodox Christianity there is not an identity between the spark and God. union of the human spirit with God takes place--union so complete that the word deification is applied to it; but it is not the union of identical substances. According to Christian theology, the saint is “deified,” not because Atman is Brahman, but because God has assimilated the purified human spirit in to the divine substance by an act of grace. Islamic theology seems to make a similar distinction. The Sufi, Mansur, was executed for giving to the words “union” and “deification” the literal meaning which they bear in the Hindu tradition. For our present purposes, however, the significant fact is that these words are actually used by Christians and Mohammedans to describe the empirical facts of metaphysical realization by means of direct, super-rational intuition.In regard to man’s final end, all the higher religions are in complete agreement. The purpose of human life is the discovery of Truth, the unitive knowledge of the Godhead. The degree to which this unitive knowledge is achieved here on earth determines the degree to which it will be enjoyed in the posthumous state. Contemplation of truth is the end, action the means. In India, in China, in ancient Greece, in Christian Europe, this was regarded as the most obvious and axiomatic piece of orthodoxy. The invention of the steam engine produced a revolution, not merely in industrial techniques, but also much more significantly in philosophy. Because machines could be made progressively more and more efficient, Western man came to believe that men and societies would automatically register a corresponding moral and spiritual improvement. Attention and allegiance came to be paid, not to Eternity, but to the Utopian future. External circumstances came to be regarded as more important that states of mind about external circumstances, and the end of human life was held to be action, with contemplation as a means to that end. These false and historically, aberrant and heretical doctrines are now systematically taught in our schools and repeated, day in, day out, by those anonymous writers of advertising copy who, more than any other teachers, provide European and American adults with their current philosophy of life. And so effective has been the propaganda that even professing Christians accept the heresy unquestioningly and are quite unconscious of its complete incompatibility with their own or anybody else’s religion.These four doctrines constitute the Perennial Philosophy in its minimal and basic form. A man who can practice what the Indians call Jnana yoga (the metaphysical discipline of discrimination between the real and teh apparent) asks for nothing more. This simple working hypothesis is enough for his purposes. But such discrimination is exceedingly difficult and can hardly be practiced, at any rate in the preliminary stages of the spiritual life, except by persons endowed with a particular kind of mental constitution. That is why most statements of the Perennial Philosophy have included another doctrine, affirming the existence of one or more human Incarnations of the Divine Ground, by whose mediation and grace the worshipper is helped to achieve his goal--that unitive knowledge of the Godhead, which is man’s eternal life and beatitude. The Bhagavad-Gita is one such statement. Here, Krishna is an Incarnation of the Divine Ground in human form. Similarly, in Christian and Buddhist theology, Jesus and Gotama are Incarnations of divinity. But whereas in Hinduism and Buddhism more than one Incarnation of the Godhead is possible (and is regarded as having in fact taken place), for Christians there has been and can be only one.An Incarnation of the Godhead and, to a lesser degree, any theocentric saint, sage or prophet is a human being who knows Who he is and can therefore effectively remind other human beings of what htey have allowed themselves to forget: namely, that if they choose to become what potentially they already are, they too can be eternally united with the Divine Ground.Worship of the Incarnation and contemplation of his attributes are for most men and women the best preparation for unitive knowledge of the Godhead. But whether the actual knowledge itself can be achieved by this means is another question. Many Catholic mystics have affirmed that, at a certain stage of that contemplative prayer in which, according to the most authoritative theologians, the life of Christian perfection ultimately consists, it is necessary to put aside all thought of the Incarnation as distracting from the higher knowledge of that which has been incarnated. From this fact have arisen misunderstandings in plenty and a number of intellectual difficulties. Here, for example, is what Abbot Josh Chapman writes in one of his admirable Spiritual Letters: “The problem of reconciling (not merely uniting) mysticism with Christianity is more difficult. The Abbot (Abbot Marmion) says that St. John of the Cross is like a sponge full of Christianity. You can squeeze it all out, and the full mystical theory remains. Consequently, for fifteen years or so, I hated St. John of the Cross and called him a Buddhist. I loved St. Teresa, and read her over and over again. She is first a Christian, only secondarily a mystic. Then I found that I had wasted fifteen years, so far as prayer was concerned.” And yet, he concludes, in spite of its “Buddhistic” character, the practice of mysticism (or, to put it in other terms, the realization of the Perennial Philosophy) makes good Christians. He might have added that it also makes good Hindus, good Buddhists, good Taoists, good Moslems and good Jews.The solution to Abbot Chapman’s problem must be sought in the domain, not of philosophy, but of psychology. Human beings are not born identical. There are many different temperaments and constitutions; and within each psycho-physical class one can find people at very different stages of spiritual development. Forms of worship and spiritual discipline which may be valuable for one individual maybe useless or even positively harmful for another belonging to a different class and standing, within that class, at a lower or higher level of development. All this is clearly set forth in the Gita, where the psychological facts are linked up with general cosmology by means of the postulate of the gunas. Krishna, who is here the mouth-piece of Hinduism in all its manifestations, finds it perfectly natural that different men should have different methods and even apparently differently objects of worship. All roads lead to Rome--provided, of course, that it is Rome and not some other city which the traveler really wishes to reach. A similar attitude of charitable inclusiveness, somewhat surprising in a Moslem, is beautifully expressed in the parable of Moses and the Shepherd, told by Jalauddin Rumi in the second book of the Masnavi. And within the more exclusive Christian tradition these problems of temperament and degree of development have been searchingly discussed in their relation to the way of Mary and the way of Martha in general, and in particular to the vocation and private devotion of individuals.We now have to consider the ethical corollaries of the perennial Philosophy. “Truth,” says St. Thomas Aquinas, “is the last end for the entire universe, and the contemplation of truth is the chief occupation of wisdom.” The moral virtues, he says in another place, belong to contemplation, not indeed essentially, but as a necessary predisposition. Virtue, in other words, is not the end, but the indispensable means to the knowledge of the divine reality. Shankara, the greatest of the Indian commentators on the Gita, hold the same doctrine. Right action is the way to knowledge; for it purifies the mind, and it is only to a mind purifies from egotism that the intuition of the Divine Ground can come.Self-abnegation, according to the Gita, can be achieved by the practice of two all-inclusive virtues--love and non-attachment. the latter is the same thing as that “holy indifference,” on which St. Francois de Sales is never tired of insisting. “He who refers every action to God,” writes Camus, summarizing his master’s teaching, “and has no aims save His Glory, will find rest everywhere, even amidst the most violent commotions.” So long as we practice this holy indifference to the fruits of action, “no lawful occupation will separate us from God; on the contrary, it can be made a means of closer union.” Here the word “lawful” supplies a necessary qualification to a teaching which, without it, is incomplete and even potentially dangerous. Some actions are intrinsically evil or inexpedient; and no good intentions, no conscious offering them to God, no renunciation of the fruits can alter their essential character. Holy indifference requires to be taught in conjunction not merely with a set of commandments prohibiting crimes, but also with a clear conception of what in Buddha’s Eightfold Path is called “right livelihood.” Thus, for the Buddhist, right livelihood was incompatible with the making of deadly weapons and of intoxicants; for the mediaeval Christian, with the taking of interest and with various monopolistic practices which have since come to be regarded as legitimate good business. John Woolman, the American Quaker, provides a most enlightening example of the way in which a man may live in the world, while practicing perfect non-attachment and remaining acutely sensitive to the claims of right livelihood. Thus, while it would have been profitable and perfectly lawful for him to see West Indian sugar and rum to the customers who came to his shop, Woolman refrained from doing so, because these things were the products of slave labor. Similarly, when he was in England, it would have been both lawful and convenient for him to travel by stage coach. Nevertheless, he preferred to make his journeys on foot. Why? Because the comforts of rapid travel could only be bought at the expense of great cruelty to the horses and the most atrocious working conditions for the post-boys. In Woolman’s eyes, such a system of transportation was intrinsically undesirable, and no amount of personal non-attachment could make it anything but undesirable. So he shouldered his knapsack and walked.In the preceding pages I have tried to show that the Perennial Philosophy and its ethical corollaries constitute a Highest Common Factor, present in all the major religions of the world. To affirm this truth has never been more imperatively necessary than at the present time. There will never be enduring peace unless and until human beings come to accept a philosophy of life more adequate to the cosmic and psychological facts than the insane idolatries of nationalism and the advertising man’s apocalyptic faith in Progress towards a mechanized New Jerusalem. All the elements of this philosophy are present, as we have seen, in the traditional religions. But in existing circumstances there is not the slightest chance that any of the traditional religions will obtain universal acceptance. Europeans and Americans will see no reason for being converted to Hinduism, say, or Buddhism. And the people of Asia can hardly be expected to renounce their own traditions for the Christianity professed, often sincerely, by the imperialists who, for four hundred years and more, have been systematically attacking, exploiting, and oppressing, and are now trying to finish off the work of destruction by “educating” them. But happily there is the Highest Common Factor of all religions, the Perennial Philosophy which has always and everywhere been the metaphysical system of prophets, saints and sages. It is perfectly possible for people to remain good Christians, Hindus, Buddhists, or Moslems and yet to be united in full agreement on the basic doctrines of the Perennial Philosophy.