[34] He would later say that there are three things that his father left him: "first of all, love of knowledge for our own Persian culture, our religious, literary, philosophical tradition; secondly, an avid interest in what was going on in the West in the realm of science and philosophy, literature and everything else; thirdly, a sense of serenity that he had within himself.

[36] When he realized, after an encounter with the philosopher Bertrand Russell, that the study of physics would not bring answers to his questions, he enrolled in additional courses on metaphysics and philosophy with Giorgio de Santillana[36] who introduced him to the works of René Guénon.

[51] I belonged to a new generation and was able to exercise much influence not only at Tehran University but also in the cultural and educational life of the country as a whole since I was a member of all the important national councils in those fields, [...] So there was a really formidable jihād on my hands to try to turn things around and to make Iranian society more aware of its own heritage.

During that time, Nasr, Tabataba'i, William Chittick, Peter Lamborn Wilson, Kenneth Morgan, Sachiko Murata, Toshihiko Izutsu, and Henry Corbin held various philosophical discourses.

[63] He is regularly invited to give courses and conferences at various institutions and universities of the five different continents on the major themes for which he has become well known:[64] Islam, philosophy, metaphysics, cosmology, anthropology, spirituality, religion, science, ecology, literature, art, etc.

For him, Nasr's works are characterized by "rigorous scholarly methodology, an encyclopedic erudition about all matters Islamic, a robustness of critical thought, and a sustained clarity of expression"; and he is "the foremost traditionalist thinker" to base himself on "eternal wisdom (sophia perennis)" in order to provide a solution to the contemporary environmental crisis.

[73] When he discovered the writings of the most influential members of what would become the Traditionalist or Perennialist school (René Guénon, Frithjof Schuon, Ananda Coomaraswamy, Titus Burckhardt, Martin Lings), the student Nasr fully aligned himself to their perspective founded on the philosophia perennis.

Nasr holds that traditional wisdom or the sophia perennis "has always seen God as Reality and the world as a dream from which the sage awakens through [spiritual] realization ... and the ordinary man through death".

[99] Thus, Nasr rejects biology's modern evolutionary synthesis, which he thinks is a "desperate attempt to substitute a set of horizontal, material causes in a unidimensional world to explain effects whose causes belong to other levels of reality".

[104] But, "because of man's separation from his original perfection", a consequence "of what Christianity calls the fall", itself followed by further declines, these faculties no longer operate invariably according to their "theomorphic nature".

[109] According to Nasr, "man contains within himself many levels of existence" that "the Western tradition" synthesises in the ternary "spirit, soul, and body (pneuma, psychē, and hylē or spiritus, anima, and corpus".

[85] Nasr contends that this wisdom, which corresponds – beyond salvation -– to deliverance from the bonds of all limitation,[127] "is present in the heart of all traditions", whether it be the Hindu Vedanta, Buddhism, the Jewish Kabbalah, the Christian metaphysics of an Eckhart or an Erigena, or Sufism.

[134]For Nasr, true metaphysics – the scientia sacra –, which is the intellectual foundation of the Traditionalist School, "is the science of the Real; of the origin and the end of things; of the Absolute and in its light, the relative"[135] and, as a corollary, of the degrees of existence.

[105] Each new "descent" of a revelation brings a particular "spiritual genius", "fresh vitality, uniqueness and the grace which make its rites and practices operative, not to speak of the paradisal vision which constitutes the origin of its sacred art or of the sapience which lies at the heart of its message".

[147] Daoud Riffi emphasizes that Sufism is the spiritual path followed by Seyyed Hossein Nasr in a universalist framework which attests to the principial unity of all major religions.

[162] For Nasr, "one of the reasons why it is so difficult to have a deep religious dialogue today" with Christians, is due – besides their conviction "that there is no salvation outside the Church"[163][note 8] – to the absence of an "esoteric dimension, interior [...], mystical", which centuries of secularism have stifled.

[165] In Knowledge and the Sacred, Nasr defines tradition as follows: Tradition as used in its technical sense [...], means truths or principles of a divine origin revealed or unveiled to mankind and, in fact, a whole cosmic sector through various figures envisaged as messengers, prophets, avatāras, the Logos or other transmitting agencies, along with all the ramifications and applications of these principles in different realms including law and social structure, art, symbolism, the sciences, and embracing of course Supreme Knowledge along with the means for its attainment.

[183] Nasr corroborates the observation that the development of the current economic system rests largely on human passions, which it feeds in its turn, thus generating a continuous blossoming of new needs which, in reality, are only desires.

[173] Realizing then, by this interior transformation, that true happiness is not linked to consumption,[192] the human being will recognize his "real and not imagined needs",[187] the only solution to slow down the uncontrolled appetite which leads to the daily rape of the planet.

[201] Thus, as Joseph E. B. Lumbard notes, for Nasr, "only tradition can provide the weapon necessary to carry out the vital battle for the preservation of the things of the spirit in a world which would completely devour man as a spiritual being if it could".

[196] According to Nasr: To defend the traditional point of view is not to negate the reality of all kinds of evil in the premodern world ranging from wars to philosophical skepticism among the Greeks in the dying moments of that civilization.

[211] As an alternative, Nasr defends his vision of an Islamic philosophy of science that accepts "limited biological changes" occurring throughout time, but rejects the idea that solely natural mechanisms account for what he calls "creativity".

[212] Nasr contends that evolutionism is one of the cornerstones of the contemporary worldview and has contributed directly to the modern world's degradation of the spiritual significance and sacredness of God's creation, as stated in "sacred scriptures" such as the Quran.

[208] Commenting on an article that Muhammad Suheyl Umar dedicated to him, Nasr speaks of his own "philosophical position": I am a follower of that philosophia perennis and also universalis, that eternal sophia, which has always been and will always be and in whose perspective there is but one Reality which can say "I" [...] I have tried to become transparent before the ray of Truth that shines whenever and wherever the veil before it is lifted or rent asunder.

Once that process is achieved, the understanding, "observation" and explication of the manner in which that light shines upon problems of contemporary man constitute for me philosophical creativity in the deepest sense of the term.

[213]For Nasr, the true "love of wisdom" (philosophia) was shared by all civilizations until the emergence, in the West, of a thought which dissociated itself more and more from the spiritual dimension[214] as a result of the occultation of the sapiential core of religion and the divorce of philosophical intelligence from faith.

Apart from the case of certain Greek currents such as sophistry and skepticism,[215] as well as the episode of nominalism towards the end of the Middle Ages,[216] it was really during the Renaissance, continues Nasr, that "the separation of philosophy and of revelation" began,[217] despite the maintenance in certain isolated circles of a true spirituality.

[220] Several works by Nasr support critical analyzes of those he considers to be engines of modern deviation: Descartes, Montaigne, F. Bacon, Voltaire, Hume, Rousseau, Kant, Comte, Darwin, Marx, Freud, Aurobindo, Teilhard de Chardin and others.

In addition, his writings abundantly cite those who, for him, convey authentic wisdom: Pythagoras, Socrates, Plato, Plotinus, Augustine, Shankara, Erigena, Avicenna, al-Bīrūnī, Suhrawardī, Ibn Arabī, Rūmī, Thomas Aquinas, Eckhart, Dante, Mullā Sadrā, Guénon, Schuon, Coomaraswamy, Burckhardt, Lings, etc.

[229] Scientism presents "modern science not as a particular way of knowing nature, but as a complete and totalitarian philosophy which reduces all reality to the physical domain and does not wish under any condition to accept the possibility of the existence of non-scientistic worldviews".