|Part of a series on|
The Perennial philosophy (Latin: philosophia perennis), also referred to as Perennialism, is a perspective in the philosophy of religion which views each of the world's religious traditions as sharing a single, universal truth from which all esoteric and exoteric knowledge and doctrine has grown.
In the early 19th century this idea was popularised by the Transcendentalists. Towards the end of the 19th century the Theosophical Society further popularized the concept under the name of "Wisdom-Religion" or "Ancient Wisdom". In the 20th century it was popularized in the English-speaking world through Aldous Huxley's book The Perennial Philosophy as well as by the strands of thought which culminated in the New Age movement.
Perennialism is a perspective within the philosophy of religion which views each of the world's religious traditions as sharing a single, universal truth on which the foundation of all religious knowledge and doctrine has grown. According to this view, each world religion, including but not limited to Christianity, Islam, Judaism, Hinduism, Taoism, Confucianism, Shinto, Sikhism, and Buddhism, is an interpretation of this universal truth adapted to cater for the psychological, intellectual, and social needs of a given culture of a given period of history. The universal truth which lives at heart of each religion has been rediscovered in each epoch by saints, sages, prophets, and philosophers. These include not only the 'founders' of the world's great religions but also gifted and inspired mystics, theologians, and preachers who have revived already existing religions when they had fallen into empty platitudes and hollow ceremonialism.
Perennialists argue that although the sacred scriptures of the world religions are undeniably diverse and often superficially oppose each other, one can discern a common doctrine regarding the ultimate purpose of human life. Typically this doctrine is posited as mystical insofar as it views the summum bonum of human life as an experiential union with the supreme being (sometimes perceived as an "energy" such as the universe) which can only be achieved by undertaking a programme of physical and mental 'purification' or 'improvement'.
Perennialism may be contrasted with conventional religious orthodoxy, which demarcates clear lines of truth and falsehood separating religions, and also with historicism, which sees religious phenomena as determined by sociopolitical context with no absolute essence.
Indo-Greek cultural exchange
During classical antiquity, Alexander the Great's campaigns brought about exchange of cultural ideas on its path throughout most of the known world of his era. The Greek Eleusinian Mysteries and Dionysian Mysteries mixed with such influences as the Cult of Isis, Mithraism and Hinduism, along with some Persian influences. Such cross-cultural exchange was not new to the Greeks; the Egyptian god Osiris and the Greek god Dionysus had been equated as Osiris-Dionysus by the historian Herodotus as early as the 5th century BC (see Interpretatio graeca).
Ariel and Will Durant in their book, The Story of Civilization as well as Thomas McEvilley in his book, The Shape of Ancient Thought mentions this sharing of the Greek and Indian cultures and its influence on Hellenistic religion.
Philo of Alexandria
The syncretic tradition of reconciling different beliefs arguably started before Philo, but Philo himself attempted to reconcile Greek Rationalism with the Torah which helped pave the way for Christianity with Neo Platonism and the adoption of the Old Testament with Christianity as opposed to Gnostic Marcion roots of Christianity.
The Perennial philosophy originates from neo-Platonism and Christianity.
Marsilio Ficino (1433–1499) argued that there is an underlying unity to the world, the soul or love, which has a counterpart in the realm of ideas. Platonic Philosophy and Christian theology both embody this truth. Ficino was influenced by a variety of philosophers including Aristotelian Scholasticism and various pseudonymous and mystical writings. Ficino saw his thought as part of a long development of philosophical truth, of ancient pre-Platonic philosophers (including Zoroaster, Hermes Trismegistus, Orpheus, Aglaophemus and Pythagoras) who reached their peak in Plato. The Prisca theologia, or venerable and ancient theology, which embodied the truth and could be found in all ages, was a vitally important idea for Ficino.
Giovanni Pico della Mirandola (1463–94), a student of Ficino, went further than his teacher by suggesting that truth could be found in many, rather than just two, traditions. This proposed a harmony between the thought of Plato and Aristotle, and saw aspects of the Prisca theologia in Averroes, the Koran, the Cabala among other sources. After the deaths of Pico and Ficino this line of thought expanded, and included Symphorien Champier, and Francesco Giorgio.
De perenni philosophia libri X
The term perenni philosophia was first used by Agostino Steuco (1497–1548) who used it to title a treatise, De perenni philosophia libri X, published in 1540. De perenni philosophia was the most sustained attempt at philosophical synthesis and harmony. Steuco represents the liberal wing of 16th-century Biblical scholarship and theology, although he rejected Luther and Calvin. De perenni philosophia, is a complex work which only contains the term philosophia perennis twice. It states that there is "one principle of all things, of which there has always been one and the same knowledge among all peoples." This single knowledge (or sapientia) is the key element in his philosophy. In that he emphasises continuity over progress, Steuco's idea of philosophy is not one conventionally associated with the Renaissance. Indeed, he tends to believe that the truth is lost over time and is only preserved in the prisci theologica. Steuco preferred Plato to Aristotle and saw greater congruence between the former and Christianity than the latter philosopher. He held that philosophy works in harmony with religion and should lead to knowledge of God, and that truth flows from a single source, more ancient than the Greeks. Steuco was strongly influenced by Iamblichus's statement that knowledge of God is innate in all, and also gave great importance to Hermes Trismegistus.
Steuco's perennial philosophy was highly regarded by some scholars for the two centuries after its publication, then largely forgotten until it was rediscovered by Otto Willmann in the late part of the 19th century. Overall, De perenni philosophia wasn't particularly influential, and largely confined to those with a similar orientation to himself. The work was not put on the Index of works banned by the Roman Catholic Church, although his Cosmopoeia which expressed similar ideas was. Religious criticisms tended to the conservative view that held Christian teachings should be understood as unique, rather than seeing them as perfect expressions of truths that are found everywhere. More generally, this philosophical syncretism was set out at the expense of some of the doctrines included within it, and it is possible that Steuco's critical faculties were not up to the task he had set himself. Further, placing so much confidence in the prisca theologia, turned out to be a shortcoming as many of the texts used in this school of thought later turned out to be bogus. In the following two centuries the most favourable responses were largely Protestant and often in England.
Gottfried Leibniz later picked up on Steuco's term. The German philosopher stands in the tradition of this concordistic philosophy; his philosophy of harmony especially had affinity with Steuco's ideas. Leibniz knew about Steuco's work by 1687, but thought that De la Verite de la Religion Chretienne by Huguenot philosopher Phillippe du Plessis-Mornay expressed the same truth better. Steuco's influence can be found throughout Leibniz's works, but the German was the first philosopher to refer to the perennial philosophy without mentioning the Italian.
Transcendentalism and Unitarian Universalism
Ralph Waldo Emerson (1803–1882) was a pioneer of the idea of spirituality as a distinct field. He was one of the major figures in Transcendentalism, an early 19th-century liberal Protestant movement, which was rooted in English and German Romanticism, the Biblical criticism of Herder and Schleiermacher, and the skepticism of Hume. The Transcendentalists emphasised an intuitive, experiential approach of religion. Following Schleiermacher, an individual's intuition of truth was taken as the criterion for truth. In the late 18th and early 19th century, the first translations of Hindu texts appeared, which were also read by the Transcendentalists, and influenced their thinking. They also endorsed universalist and Unitarianist ideas, leading to Unitarian Universalism, the idea that there must be truth in other religions as well, since a loving God would redeem all living beings, not just Christians.
Many perennialist thinkers (including Armstrong, Huston Smith and Joseph Campbell) are influenced by Hindu reformer Ram Mohan Roy and Hindu mystics Ramakrishna and Swami Vivekananda., who themselves have taken over western notions of universalism. They regarded Hinduism to be a token of this Perennial Philosophy. This notion has influenced thinkers who have proposed versions of the perennial philosophy in the 20th century.
The unity of all religions was a central impulse among Hindu reformers in the 19th century, who in turn influenced many 20th-century perennial philosophy-type thinkers. Key figures in this reforming movement included two Bengali Brahmins. Ram Mohan Roy, a philosopher and the founder of the modernising Brahmo Samaj religious organisation, reasoned that the divine was beyond description and thus that no religion could claim a monopoly in their understanding of it.
The mystic Ramakrishna's spiritual ecstasies included experiencing the sameness of Christ, Mohammed and his own Hindu deity. Ramakrishna's most famous disciple, Swami Vivekananda, travelled to the United States in the 1890s where he formed the Vedanta Society.
Roy, Ramakrishna and Vivekananda were all influenced by the Hindu school of Advaita Vedanta, which they saw as the exemplification of a Universalist Hindu religiosity.
By the end of the 19th century the idea of a Perennial Philosophy was popularized by leaders of the Theosophical Society such as H. P. Blavatsky and Annie Besant, under the name of "Wisdom-Religion" or "Ancient Wisdom". The Theosophical Society took an active interest in Asian religions, subsequently not only bringing those religions under the attention of a western audience,but also influencing Hinduism, and Buddhism in Sri Lanka and Japan.
The emphasis in the Perennial Philosophy has shifted from the soul or love as unifying essence, to religious experience and the notion of nonduality or "altered state of consciousness." William James popularized the use of the term "religious experience" in his The Varieties of Religious Experience. It has also influenced the understanding of mysticism as a distinctive experience which supplies knowledge.
Wayne Proudfoot traces the roots of the notion of "religious experience" further back to the German theologian Friedrich Schleiermacher (1768–1834), who argued that religion is based on a feeling of the infinite. The notion of "religious experience" was used by Schleiermacher to defend religion against the growing scientific and secular critique. It was adopted by many scholars of religion, of which William James was the most influential.
Critics point out that the emphasis on "experience" favours the atomic individual, instead of the community. It also fails to distinguish between episodic experience, and mysticism as a process, embedded in a total religious matrix of liturgy, scripture, worship, virtues, theology, rituals and practices. Richard King also points to disjunction between "mystical experience" and social justice:
The privatisation of mysticism - that is, the increasing tendency to locate the mystical in the psychological realm of personal experiences - serves to exclude it from political issues such as social justice. Mysticism thus comes to be seen as a personal matter of cultivating inner states of tranquility and equanimity, which, rather than serving to transform the world, reconcile the individual to the status quo by alleviating anxiety and stress.
A similar criticism is voiced by critics of Neo-Advaita, a popularised western version of Neo-Vedanta primarily based on the teachings of Ramana Maharshi. Those critics point out that the "experience" of a nondual reality does not suffice to gain insight into the workings of the mind. Jacobs warns that Advaita Vedanta committed practice takes years to sever the "occlusion" of the so-called "vasanas, samskaras, bodily sheaths and vrittis", and the "granthi or knot forming identification between Self and mind":
The main Neo-Advaita fallacy ignores the fact that there is an occlusion or veiling formed by vasanas, samskaras, bodily sheaths and vrittis, and there is a granthi or knot forming identification between Self and mind, which has to be undone [...] The Maharshi's remedy to this whole trap is persistent effective Self-enquiry, and/or complete unconditional surrender of the 'phantom ego' to Self or God, until the granthi is severed, the vasanas are rendered harmless like a burned out rope.
The term was popularized in more recent times by Aldous Huxley, who was profoundly influenced by Vivekananda's Neo-Vedanta and Universalism, in his 1945 book: The Perennial Philosophy. He defined the perennial philosophy as:
[...] the metaphysic that recognizes a divine Reality substantial to the world of things and lives and minds; the psychology that finds in the soul something similar to, or even identical to, divine Reality; the ethic that places man's final end in the knowledge of the immanent and transcendent Ground of all being;
the thing is immemorial and universal. Rudiments of the perennial philosophy may be found among the traditional lore of primitive peoples in every region of the world, and in its fully developed forms it has a place in every one of the higher religions.
He also pointed out the method of the Buddha:
The Buddha declined to make any statement in regard to the ultimate divine Reality. All he would talk about was Nirvana, which is the name of the experience that comes to the totally selfless and one-pointed. […] Maintaining, in this matter, the attitude of a strict operationalist, the Buddha would speak only of the spiritual experience, not of the metaphysical entity presumed by the theologians of other religions, as also of later Buddhism, to be the object and (since in contemplation the knower, the known and the knowledge are all one) at the same time the subject and substance of that experience.
and that in the Upanishads:
The Perennial Philosophy is expressed most succinctly in the Sanskrit formula, tat tvam asi ('That thou art'); the Atman, or immanent eternal Self, is one with Brahman, the Absolute Principle of all existence; and the last end of every human being, is to discover the fact for himself, to find out who he really is.
According to Aldous Huxley, in order to apprehend the divine reality, one must choose to fulfill certain conditions: "making themselves loving, pure in heart and poor in spirit." Huxley argues that very few people can achieve this state. Those who have fulfilled these conditions, grasped the universal truth and interpreted it have generally been given the name of saint, prophet, sage or enlightened one. Huxley argues that those who have, "modified their merely human mode of being," and have thus been able to comprehend "more than merely human kind and amount of knowledge" have also achieved this enlightened state.
The Traditionalist School was a group of 20th century thinkers concerned with what they considered to be the demise of traditional forms of knowledge, both aesthetic and spiritual, within Western society. The principal thinkers in this tradition are René Guénon, Ananda Coomaraswamy and Frithjof Schuon. Other important thinkers in this tradition include Titus Burckhardt, Martin Lings, Jean-Louis Michon, Marco Pallis, Huston Smith, Hossein Nasr, Jean Borella and Julius Evola. A central concept of this school is that of the perennial philosophy based upon an ancient belief that all the world's great religions share the same origin (in a primordial principle of transcendent unity) and are, at root, based on the same metaphysical principles. These ideas are sometimes referred to in the Latin as philosophia perennis.
According to the Traditionalist School, the "philosophia perennis" designates a worldview that is opposed to the scientism of modern secular societies and which promotes the rediscovery of the wisdom traditions of the pre-secular developed world. This view is exemplified by Rene Guenon in his magnum opus and one of the founding works of the traditionalist school, The Reign of Quantity and The Sign of the Times.
According to Frithjof Schuon:
It has been said more than once that total Truth is inscribed in an eternal script in the very substance of our spirit; what the different Revelations do is to "crystallize" and "actualize", in different degrees according to the case, a nucleus of certitudes which not only abides forever in the divine Omniscience, but also sleeps by refraction in the "naturally supernatural" kernel of the individual, as well as in that of each ethnic or historical collectivity or of the human species as a whole.
The idea of a Perennial Philosophy is central to the New Age Movement. The New Age movement is a Western spiritual movement that developed in the second half of the 20th century. Its central precepts have been described as "drawing on both Eastern and Western spiritual and metaphysical traditions and infusing them with influences from self-help and motivational psychology, holistic health, parapsychology, consciousness research and quantum physics". The term New Age refers to the coming astrological Age of Aquarius.
The New Age aims to create "a spirituality without borders or confining dogmas" that is inclusive and pluralistic. It holds to "a holistic worldview", emphasising that the Mind, Body and Spirit are interrelated and that there is a form of monism and unity throughout the universe. It attempts to create "a worldview that includes both science and spirituality" and embraces a number of forms of mainstream science as well as other forms of science that are considered fringe.
Appearance in world religions and philosophies
Below is a cursory glance at the ways in which the idea of a sophia perennis et universalis can be found in the world's religions and philosophies.
Progressive revelation is a core teaching in the Bahá'í Faith that suggests that religious truth is revealed by God progressively and cyclically over time through a series of divine Messengers, and that the teachings are tailored to suit the needs of the time and place of their appearance. Thus, the Bahá'í teachings recognize the divine origin of several world religions as different stages in the history of one religion, while believing that the revelation of Bahá'u'lláh is the most recent (though not the last—that there will never be a last), and therefore the most relevant to modern society.
The general theme of the successive and continuous religions founded by messengers of God is that there is an evolutionary tendency, and that each messenger brings a larger measure of revelation (or religion) to humankind than the previous one. The differences in the revelation brought by the messengers is stated to be attributed to the various worldly, societal and human factors; these differences are in accordance with the conditions and requirements of the time that the messenger came. Bahá'u'lláh, the founder of the Bahá'í Faith, explained that the appearance of successive messengers was like the annual coming of Spring, which brings new life to the world which has come to neglect the teachings of the previous messenger.
The following statement by Saint Augustine can be taken as an assertion of the perennial philosophy.:
The very thing that is now called the Christian religion was not wanting among the ancients from the beginning of the human race, until Christ came in the flesh, after which the true religion, which had already existed, began to be called "Christian".
Others see this statement as expressing the Roman Catholic notion of semina verbi ("seeds of the word"), whereby there is some truth (seeds of truth) in pre-Christian Greek thought, but these required purification by the light of the Gospels. This idea was current among many other early Christians including Clement of Alexandria, Origen, Basil of Caesarea, Gregory of Nyssa, and Leo the Great as well as Augustine.
Heraclitus of Ephesus, one of the Pre-Socratics and a priest of the Temple of Artemis, 6th century BC, speaks of Divinity (ὁ θεός) in this way: "God is day night, winter summer, war peace, satiety hunger, assuming various forms, just as fire when it is mingled with different kinds of incense is named according to the smell of each." Cicero mentions 'universal religion' in his Tusculan Disputations. Ammonius Saccas in the 3rd century tried to reconcile differing religious philosophies.
From the beginning, Islam has considered itself to be the final flourishing of perennial wisdom before the "end of times". The Qur'an is replete with references to earlier religious figures from the Jewish and Christian traditions, considering that Abraham, Moses, Jesus, Mary and other holy figures were always muslim (i.e. they were followers of the oneness of god). The idea of a single religious truth is more apparent at a deeper level of Islam, such as Sufism or mystical traditions of Islam, with parallelisms in the Judaeo-Christian and Hindu tradition, than it is among scholars dealing with doctrinal issues, who recognise the Jewish and Christian truths, and possibility of non-Abrahamic traditions, but by necessity reject all beliefs that seem contrary to Islam (such as the Trinity, the sonship of Christ, or the reality of the crucifixion). Modern Islamist movements, on the other hand (e.g. Salafism), tend to reject entirely all other religious traditions as also the diversity among Muslim communities.
Al-Farabi (872–950) advocated the idea of philosophy and religion being two avenues to the same truth. His own personal philosophy strongly emphasized a classification of knowledge and science on the basis of methodology. Thus, he described his notion of an esoteric philosophy which referenced the eternal truth or wisdom which lies at the heart of all traditions as a "science of reality" based on the method of "certain demonstration" (al-burhan al-yaqini). This method is a combination of intellectual intuition and logical conclusions of certainty (istinbat). He reasoned that it was therefore a superior kind of knowledge to the exoteric domain of religions (millah) since that relied on a method of persuasion (al-iqna), not demonstration. This philosophy is compared with the philosophia perennis of Leibniz and later in the 20th century, Frithjof Schuon. Al-Farabi developed a theory to explain the diversity of religions. He posited that religions differed from one another because the same spiritual and intellectual truths can have different "imaginative representations". He further stated that there was a unity of all revealed traditions at the philosophical level, since all nations and peoples must have a philosophical account of reality that is one and the same.
The Tirukkuṛaḷ by Tiruvalluvar is noted as the perrenial philosophy of the Tamil culture. It was composed during the late Sangam period and is the oldest and most revered among the secular Tamil books of Law. Tiruvalluvar, whose social and religious identity is only theorised by scholars, presents a philosophy that is rationalistic, secular and universal. The Istituto Italiano per l'Africa e l'Oriente noted that Tirukkural transcends all the physical limits like clan, clime, creed and colour. It is split into the three aspects, or முப்பால் (muppāl) viz. அறம் (virtue), பொருள் (material) and இன்பம் (pleasure). Its chapters covers all aspects of human life in 1330 couplets from அமைச்சு (The establishment [of bureaucracy]) to அன்புடமை (The possession of Love).
The idea of a perennial philosophy, sometimes called perennialism, is a key area of debate in the academic discussion of mystical experience. Writers such as WT Stace, Huston Smith, and Robert Forman argue that there are core similarities to mystical experience across religions, cultures and eras.
For Stace the universality of this core experience is a necessary, although not sufficient, condition for one to be able to trust the cognitive content of any religious experience. Karen Armstrong's writings on the universality of a golden rule can also be seen as a form of perennial philosophy.
Perennial philosophy and religious pluralism
Religious pluralism holds that various world religions are limited by their distinctive historical and cultural contexts and thus there is no single, true religion. There are only many equally valid religions. Each religion is a direct result of humanity's attempt to grasp and understand the incomprehensible divine reality. Therefore, each religion has an authentic but ultimately inadequate perception of divine reality, producing a partial understanding of the universal truth, which requires syncretism to achieve a complete understanding as well as a path towards salvation or spiritual enlightenment.
Although perennial philosophy also holds that there is no single true religion, it differs when discussing divine reality. Perennial philosophy states that the divine reality is what allows the universal truth to be understood. Each religion provides its own interpretation of the universal truth, based on its historical and cultural context. Therefore, each religion provides everything required to observe the divine reality and achieve a state in which one will be able to confirm the universal truth and achieve salvation or spiritual enlightenment.
- The Perennial Philosophy
- Rudolf Otto
- Ivan Aguéli
- Jean-Louis Michon
- Julius Evola
- Huston Smith
- William Stoddart
- Meaning of life
- The Teachings of the Mystics—Book by W.T. Stace
- Traditionalist School
- Transpersonal psychology
- Angus Macnab
- Whitall Perry
- Hossein Nasr
- Henry Corbin
- Mateus Soares de Azevedo
- Religious experience
- Wisdom tradition
- Michel de Montaigne
- Edith Stein
- Wilbur Marshall Urban
- more fully, philosophia perennis et universalis; sometimes shortened to sophia perennis or religio perennis
- See The Knot of the Heart
- Charles Schmitt, Perennial Philosophy: From Agostino Steuco to Leibniz, Journal of the History of Ideas. P. 507, Vol. 27, No. 1, (Oct. – Dec. 1966)
- Blavatsky, Helena Petrovna (1889). The Key to Theosophy. Mumbai, India: Theosophy Company (published 1997). p. 7.
- Christianity and the Perennial Philosophy, by Mateus Soares de Azevedo. Bloomington, World Wisdom, 2005
- Charles Schmitt P. 508, (1966)
- Charles Schmitt P. 513 (1966)
- Charles Schmitt P. 515 (1966)
- Schmitt (1966) p. 516
- De perenni philosophia Bk 1, Ch 1; folio 1 in Schmitt (1966) P.517
- Jamblichi De mysteriis liber, ed. Gustavus Parthey (Berlin), I, 3; 7-10
- Charles Schmitt P. 516 (1966)
- Charles Schmitt (1966) P. 527
- Charles Schmitt (1966) P. 524
- Charles Schmitt (1966) P. 530-1
- Schmidt, Leigh Eric. Restless Souls : The Making of American Spirituality. San Francisco: Harper, 2005. ISBN 0-06-054566-6
- Sharf 1995.
- Prothero p.166
- King 2002.
- Prothero, Stephen (2010) God is Not One: The Eight Rival Religions That Run the World—and Why Their Differences Matter, p. 165-6, HarperOne, ISBN 0-06-157127-X
- Hori 1999, p. 47.
- Sharf 2000, p. 271.
- Parsons 2011, p. 4-5.
- King 2002, p. 21.
- Jacobs 2004, p. 84.
- Jacobs 2004, p. 85.
- Jacobs 2004, p. 84-85.
- Roy 2003.
- The Perennial Philosophy, p. vii
- The Perennial Philosophy
- Aldous Huxley
- Huxley, Aldous. The perennial philosophy . [1st ed. New York: Harper & Brothers, 1945. p.2
- Huxley, Aldous. The perennial philosophy . [1st ed. New York: Harper & Brothers, 1945. p.3
- Huxley, Aldous. The perennial philosophy . [1st ed. New York: Harper & Brothers, 1945. p.6
- Renaud Fabbri argues that Evola should not be considered a member of the Perennialist School. See the section Julius Evola and the Perennialist School in Fabbri's Introduction to the Perennialist School
- The Essential Writings of Frithjof Schuon, Suhayl Academy, Lahore, 2001, p.67.
- Drury 2004, p. 12.
- Drury 2004, p. 8.
- Drury 2004, p. 11.
- Michael D. Langone, Ph.D. Cult Observer, 1993, Volume 10, No. 1. What Is "New Age"?, retrieved 2006-07
- Drury 2004, p. 10.
- Smith, Peter (2000). "Progressive revelation". A concise encyclopedia of the Bahá'í Faith. Oxford: Oneworld Publications. pp. 276–277. ISBN 1-85168-184-1.
- Lundberg, Zaid (May 1996). Baha'i Apocalypticism: The Concept of Progressive Revelation. Department of History of Religion at the Faculty of Theology, Lund University. Retrieved 2006-11-25.
- Cross, Stephen Coomaraswamy, St. Augustine, and the Perennial Philosophy, in Harry Oldmeadow Crossing Religious Frontiers: Studies in Comparative Religion (2010) p.73 World Wisdom, ISBN 1-935493-55-8. See also Ye Shall Know the Truth: Christianity and the Perennial Philosophy, by Mateus Soares de Azevedo. Bloomington: World Wisdom, 2005 ISBN 0-941532-69-0
- St Augustine Retractationes, 1.13.3, in Gustave Bardy (ed.) Biblioteque Augustinienne, Vol. 12 (1950), Paris, in Cross, Stephen Coomaraswamy, St. Augustine, and the Perennial Philosophy, in Harry Oldmeadow Crossing Religious Frontiers: Studies in Comparative Religion (2010) p.73 World Wisdom, ISBN 1-935493-55-8
- The New Evangelization and the Teaching of Philosophy by Bishop Allen Vigneron p. 99, in Eds. Foster, D.R. and Koterski, J.W. (2003) The two wings of Catholic thought: essays on Fides et ratio, CUA Press, ISBN 0-8132-1302-9?
- Diels-Kranz 22, B67.
- I, 15: "religio omnium".
- Thackara, W.T.S. The Perennial Philosophy, Sunrise magazine, April/May 1984
- Cf. Qur'an 5:48; 29:46 etc.
- Cf. a moving testimony from the Hadith literature in the "prayer of Abu Bakr" (with Arabic original text), the first of the four Sunni caliphs.
- See Chittick, "Islam's Attitude Towards Other Religions".
- See Khalil Andani, "The Crucifixion in Shi'a Isma'ili Islam", for an Isma'ili view.
- Classification of Knowledge in Islam by Dr. Osman Bakar, 1998, ISBN 0-946621-71-3, p.81
- Classification of Knowledge in Islam by Dr. Osman Bakar, 1998, ISBN 0-946621-71-3, p.83
- Thani Nayagam, Xavier S. (1971). Thirumathi Sornammal Endowment lectures on Tirukkural, 1959-60 to 1968-69, Part 1. University of Madras.
- Speeches of President V. V. Giri, Volume 1. Publications Division, Ministry of Information and Broadcasting, Govt. of India. 1974.
- C. Rajasingham (1987). Thirukkural, the daylight of the psyche. International Institute of Tamil Studies.
- East and west, Volume 44, Issues 2-4. Istituto italiano per il Medio ed Estremo Oriente. 1994.
- Wildman, Wesley J. (2010) Religious Philosophy as Multidisciplinary Comparative Inquiry: Envisioning a Future for the Philosophy of Religion, p. 49, SUNY Press, ISBN 1-4384-3235-6
- Prothero, Stephen (2010) God is Not One: The Eight Rival Religions That Run the World--and Why Their Differences Matter, p. 6, HarperOne, ISBN 0-06-157127-X
- Livingston, James. "Religious Pluralism and the Question of Religious Truth in Wilfred C. Smith." The Journal for Cultural and Religious Theory 4, no. 3 (2003): pp.58-65.
- Bowden, John Stephen. "Perennial Philosophy and Christianity." In Christianity: the complete guide . London: Continuum, 2005. pp.1-5.
- Mateus Soares de Azevedo, Ye Shall Know the Truth: Christianity and the Perennial Philosophy, Bloomington: World Wisdom, 2005 ISBN 0-941532-69-0
- James S. Cutsinger, The Fullness of God: Frithjof Schuon on Christianity, Bloomington, Indiana: World Wisdom, 2004
- Drury, Nevill (2004), The New Age: Searching for the Spiritual Self, London, England, UK: Thames and Hudson, ISBN 0-500-28516-0
- Ranjit Fernando (ed.) (1991), The Unanimous Tradition, Essays on the essential unity of all religions. Sri Lanka Institute of Traditional Studies, 1991 ISBN 955-9028-01-4
- Hori, Victor Sogen (1999), Translating the Zen Phrase Book. In: Nanzan Bulletin 23 (1999) (PDF)
- Aldous Huxley (1944), The Perennial Philosophy. UK: Chatto & Windus; USA: Harper & Row, Harper & Brothers. Harper Perennial 1990 edition: ISBN 0-06-090191-8, Harper Modern Classics 2004 edition: ISBN 0-06-057058-X
- John Holman (2008), The Return of the Perennial Philosophy: The Supreme Vision of Western Esotericism. Watkins Publishing, ISBN 1-905857-46-2
- Jacobs, Alan (2004), Advaita and Western Neo-Advaita. In: The Mountain Path Journal, autumn 2004, pages 81-88, Ramanasramam
- King, Richard (2002), Orientalism and Religion: Post-Colonial Theory, India and "The Mystic East", Routledge
- McMahan, David L. (2008), The Making of Buddhist Modernism, Oxford University Press, ISBN 9780195183276
- Roy, Sumita (2003), Aldous Huxley And Indian Thought, Sterling Publishers Pvt. Ltd
- Frithjof Schuon and the Perennial Philosophy, Authors Harry Oldmeadow and William Stoddart, Contributor William Stoddart, Publisher World Wisdom, Inc, (2010) ISBN 1-935493-09-4
- Sharf, Robert H. (2000), The Rhetoric of Experience and the Study of Religion. In: Journal of Consciousness Studies, 7, No. 11-12, 2000, pp. 267-87 (PDF)
- The other perennial philosophy: a metaphysical dialectic, Author Alan M. Laibelman, University Press of America, (2000), ISBN 0-7618-1827-8
- Perennial Philosophy, Brenda Jackson, Ronald L McDonald, Penguin Group (USA) ISBN 0-452-00144-7
- "The Mystery of the Two Natures", in Barry McDonald (ed.), Every Branch in Me: Essays on the Meaning of Man, Bloomington, Indiana: World Wisdom, 2002
- Parsons, William B. (2011), Teaching Mysticism, Oxford University Press
- Whitall N. Perry, A Treasury of Traditional Wisdom, Louisville, Kentucky: Fons Vitae, 2001
- Philip Sherrard, "Christianity and Other Sacred Traditions", in: Christianity: Lineaments of a Sacred Tradition, Brookline, Massachusetts: Holy Cross Orthodox Press, 1998
- Stanford Encyclopdeia of Philosophy, Transcendentalism
- Jone John Lewis, What is Transcendentalism?"
- Barry Andrews, THE ROOTS OF UNITARIAN UNIVERSALIST SPIRITUALITY IN NEW ENGLAND TRANSCENDENTALISM
- Gellman, Jerome, "Mysticism", The Stanford Encyclopedia of Philosophy (Summer 2011 Edition), Edward N. Zalta (ed.)
- David Frawley, Misconceptions about Advaita. The Mountain Path, Sri Ramanashram
- Melton, J. Gordon – Director Institute for the Study of American Religion. New Age Transformed, retrieved 2006-06
- William W. Quinn, junior. The Only Tradition, in S.U.N.Y. Series in Western Esoteric Traditions. Albany, N.Y.: State University of New York Press, 1997. xix, 384 p. ISBN 0-7914-3214-9 pbk
- Samuel Bendeck Sotillos, Psychology and the Perennial Philosophy: Studies in Comparative Religion (Bloomington, IN: World Wisdom, 2013). ISBN 978-1-936597-20-8.