What Mystics Across All Traditions Say About Oneness

Academic scholars of religion have long wrestled with what is called the "perennial philosophy" debate: is the similarity between mystical reports across traditions evidence that they describe the same underlying reality, or is the apparent similarity a projection — Western scholars imposing a template that flattens genuine differences?

This is a real debate, and the anti-perennialist position (associated with scholars like Steven Katz and Wayne Proudfoot) has genuine force. Katz argued that mystical experience is always shaped by the tradition within which it occurs — a Christian mystic has a Christian experience, a Buddhist mystic has a Buddhist experience, and the appearance of convergence is the result of selective quotation and interpretive flattening.

There is something to this. The differences between traditions are real. A Zen experience of sunyata (emptiness) is not identical to a Christian experience of union with a personal God. A Vedantic experience of Atman-Brahman identity carries metaphysical commitments that a Theravada Buddhist would reject. The furniture is different.

But here is what is striking: strip away the theological furniture — the doctrinal frameworks, the specific names for what is experienced — and what remains is a cluster of core phenomenological features that appear across traditions with remarkable consistency. Not identical. Consistent.

William James, in his 1902 Varieties of Religious Experience, identified four features shared by what he called "mystical states": ineffability (the experience cannot be fully captured in language), noetic quality (the experience feels like genuine knowledge, not just feeling), transiency (it passes, though it leaves traces), and passivity (it happens to you, not because of you). These features hold across traditions he surveyed — Christian, Jewish, Islamic, Hindu, Buddhist, indigenous — and have held up reasonably well in more recent empirical research.

Walter Stace's 1960 Mysticism and Philosophy went further, identifying seven core features of what he called "introvertive mystical experience": the sense of unity, the dissolution of time and space, the sense of reality and objectivity, the sense of blessedness or peace, the sense that what is experienced is sacred or holy, paradoxicality (the experience violates logic in ways that can only be gestured at), and ineffability. Again, cross-traditional.

The contemporary researcher Roland Griffiths at Johns Hopkins, whose psilocybin studies have produced the most rigorous empirical data on mystical-type experiences in clinical settings, found that experiences induced by psilocybin in secular research subjects — people with no particular religious commitments — matched the features James and Stace described with high fidelity. The drug was not producing a Christian experience or a Buddhist experience. It was producing something that matched the cross-traditional template.

The convergence is not nothing. Whatever mystics are pointing at, they are pointing at something.

Let me give you the primary sources directly, without intermediary.

Christian mysticism. Meister Eckhart (1260–1328), Dominican friar: "There is something in the soul which is above the soul, divine, simple, a pure nothing; rather nameless than named, rather unknown than known... Sometimes I have called it a power, sometimes an uncreated light, and sometimes a divine spark." And: "The eye through which I see God is the same eye through which God sees me; my eye and God's eye are one eye, one seeing, one knowing, one love."

Hildegard of Bingen (1098–1179): "I am the one whose praise echoes on high. I adorn all the earth. I am the breeze that nurtures all things green. I am the rain coming from the dew that causes the grasses to laugh with the joy of life."

Julian of Norwich (1342–1416), after a series of visions during a near-death illness: "All shall be well, and all shall be well, and all manner of thing shall be well." The specificity is less important than the quality: overwhelming certainty that at the deepest level of reality, there is no problem. All is already whole.

Sufi Islam. Rumi (1207–1273): "I have lived on the lip of insanity, wanting to know reasons, knocking on a door. It opens. I've been knocking from the inside." And: "You are not a drop in the ocean. You are the entire ocean in a drop."

Al-Hallaj (858–922), executed for declaring "Ana al-Haqq" — I am the Truth — which his judges interpreted as blasphemy and which he understood as the direct expression of the mystical insight that the individual self is identical with the divine reality. He died for the report.

Ibn Arabi (1165–1240), possibly the most systematically developed mystical philosophy in Islamic history: "Do not attach yourself to any particular creed exclusively, so that you may disbelieve all the rest; otherwise you will lose much good, nay, you will fail to recognize the real truth of the matter." The unity he described was prior to all theological distinctions.

Buddhist traditions. The Pali Canon records the Buddha's description of Nibbana as "the unborn, unbecome, unmade, unconditioned" — defined primarily by the negation of all the features of conditioned existence, including the sense of a separate self. The Buddha consistently refused to elaborate beyond this, because elaboration imports conceptual frames that distort the referent.

Thich Nhat Hanh's concept of "interbeing" — the term he coined to describe the Buddhist teaching of dependent origination — captures the relational, non-separate nature of all phenomena. "You cannot be, by yourself alone. You have to inter-be with every other thing." Not metaphor. Ontological claim.

Huang Po, Tang Dynasty Chan master: "The foolish reject what they see, not what they think. The wise reject what they think, not what they see." The dissolution of the interpretive overlay of selfhood reveals something that was always present.

Hindu traditions. The Chandogya Upanishad contains the most direct formulation: Uddalaka explains to his son Shvetaketu that the essence (Atman) of all living things is identical to the ground of all being (Brahman). "Tat tvam asi" — That thou art. You are that. Not you are like that, or you are connected to that. You are that.

Ramana Maharshi (1879–1950), the modern Advaita Vedanta sage, asked in his early twenties "Who am I?" and then sat with the question until the self that was asking the question dissolved. He spent the rest of his life pointing others toward the same investigation. His teaching is almost entirely negative — not "here is what you are," but "investigate the one who thinks it is asking."

Sri Aurobindo described the experience as "the disappearance of the limited personal self into a vast silent self... an immense peace and stillness and joy... a sense of absolute reality."

Jewish mysticism. Kabbalah understands the Ein Sof — the infinite, the limitless ground of being — as the true reality from which individual forms emerge through a process of contraction (tzimtzum) and emanation. Mystical practice aims at devekut — cleaving to the divine — which is understood not as union with an external other but as recognizing the true nature of what you always already are.

Abraham Abulafia, the 13th-century Kabbalist who developed contemplative practices designed to induce mystical states: "Know that the separated Intellect — that which truly understands — is both the understander, the understood, and the act of understanding itself, all in one."

The Baal Shem Tov, 18th-century founder of Hasidism: "Wherever I go, I go to Jerusalem" — meaning that the sacred is not elsewhere, the divine is not over there. The mystical geography collapses.

Indigenous traditions. Black Elk of the Oglala Sioux, as recorded by John Neihardt: "Then I was standing on the highest mountain of them all, and round about beneath me was the whole hoop of the world. And while I stood there I saw more than I can tell and I understood more than I saw; for I was seeing in a sacred manner the shapes of all things in the spirit, and the shape of all shapes as they must live together like one being."

The Andean concept of Pachamama — the living earth of which humans are part — is not metaphor. It is cosmology. The separateness of human beings from the rest of the living world is the error; embeddedness is the baseline reality.

Three claims are implicit in this convergence that deserve to be made explicit.

First: The sense of separateness is contingent, not necessary. The overwhelming weight of mystical testimony is that the ordinary sense of being a separate self — a self that ends at the skin and is fundamentally different from what is outside it — is produced by conditions, not given by the nature of reality. Specific practices, substances, or spontaneous events can dissolve it. If it were the bedrock of what a human being is, it could not be dissolved. The fact that it can be dissolved means it is a construct — a useful and persistent construct, but a construct.

Second: What remains when it is dissolved is not nothing. The mystical reports are not descriptions of absence. They are descriptions of presence — overwhelming, luminous, loving presence. This is what distinguishes the mystical state from mere dissociation or ego dissolution. Dissociation is experienced as a lessening of reality. The mystical state is experienced as its intensification. What is revealed when the sense of separation drops is not a void but a fullness.

Third: The fullness is characterized by love and recognition. Across traditions, the core emotional quality of the mystical state is described as love — not love directed toward a specific object but love as the substance or texture of what is. Rumi's reed flute crying for the reed bed. Julian's certainty that all shall be well. The Buddhist metta — lovingkindness — as the natural quality of the mind when its defensive contractions relax. If this is a consistent feature of the state, it is significant. The nervous system, at its deepest level of coherence, generates love. Not fear. Love.

The neurological study of mystical experience has advanced significantly since the 1970s. The most rigorous recent work comes from psilocybin research at Johns Hopkins and NYU.

Roland Griffiths's landmark 2006 study gave psilocybin to psychologically healthy volunteers with no prior experience with psychedelics. Sixty-seven percent described the experience as among the top five most meaningful experiences of their lives. Thirty-three percent called it the single most meaningful. Two-thirds showed measurable increases in well-being, positive mood, and life satisfaction at two months post-session. These effects held at a fourteen-month follow-up.

More recent mechanistic work points to the default mode network (DMN) as the key neural substrate. The DMN is the brain's self-referential circuitry — the network that generates and maintains the sense of a continuous, bounded self. It is active when we are not focused on external tasks: ruminating, remembering, planning, thinking about ourselves and others. Psilocybin, meditation, and other conditions associated with mystical states dramatically reduce DMN activity. The "ego" in its neurological sense is the DMN's continuous self-referential narrative. When that quiets, the report from across traditions is: what remains is unity, love, and peace.

The neuroscientist Andrew Newberg has spent decades scanning the brains of meditating monks, praying Franciscan nuns, and individuals in various states of spiritual practice. He finds consistent changes in the parietal lobe — specifically the superior parietal lobule, which he calls the "orientation association area." Its function is to create the brain's model of where the self ends and the rest of the world begins. In deep meditative states, its activity drops dramatically. The feeling of being a separate, bounded self requires active neural construction. Remove the construction — through meditation, prayer, certain substances, or apparently sometimes spontaneous grace — and the sense of separation dissolves.

The religious traditions have been doing neuroscience for three thousand years. They just called it something else.

Here is the weight of this article.

If the sense of separation is constructed rather than given, and if the construction can be dissolved, then the cruelties that flow from it — the violence done to people who are perceived as fundamentally other, the exploitation that is possible when someone genuinely does not feel the reality of another's suffering as their own — these are not fixed features of human nature. They are consequences of a particular state of consciousness. A state that can change.

This does not mean mystics are perfect. They are not. Mystical experience does not automatically produce ethical behavior. History offers ample evidence of people who had genuine unitive experiences and remained capable of cruelty, rationalization, and self-deception. The experience is not a vaccine.

But the existence of the experience tells us something. It tells us that the human nervous system contains the capacity for a mode of being in which the other is not experienced as other — in which the suffering of another is as real as your own, because the boundary between self and other has become transparent. A mode in which war, exploitation, and indifference to hunger become not just ethically wrong but experientially incoherent. You cannot hurt something you feel yourself to be.

This capacity is not restricted to saints and yogis. Psilocybin studies show it is accessible to ordinarily secular people in a single afternoon. Long-term meditators show structural brain changes consistent with a sustained, milder version of the same state. Spontaneous mystical experiences — unasked for, unprepared for — are reported by a significant minority of the general population. William James estimated one in five people in his era. More recent surveys suggest higher rates.

The capacity is there. In the hardware. Waiting.

Huxley's project — cataloguing the Perennial Philosophy — was not an exercise in interfaith niceness. It was a claim about human nature. A claim that underneath the diversity of religious expression, human beings have been circling the same insight for all of recorded history: that the feeling of separateness is an illusion, and that what is revealed when the illusion drops is love.

If that is true — if even partially true — then building a world that makes that discovery more accessible, more common, and more durable is not a spiritual luxury. It is the most practical thing we could do.

For someone reading this who is not a meditating monk and not planning a psilocybin session, what is the take?

Three things.

The first is to take the reports seriously. Not to believe them wholesale, but to genuinely consider what it means that this convergence exists. Hundreds of millions of people across history, across traditions that opposed each other theologically, politically, and militarily, have reported the same core experience. That is data. It deserves more than dismissal.

The second is to notice the moments. Most people have experienced, at some moment — in nature, in music, in intimacy, in grief, in the birth of a child or the death of a parent — some degree of the dissolution described in these reports. A moment where the sense of separation dropped and something larger was felt. These are not anomalies or errors. They are glimpses of the capacity the nervous system carries. They are worth remembering as data about what you are.

The third is to build practice. The traditions are unanimous that the experience is cultivable. Not forced — you cannot will your way to mystical union. But the conditions that make it more likely can be established: sustained meditation, contemplative prayer, extended time in nature, genuine intimacy and vulnerability, the practices of attention and devotion that every tradition has developed for exactly this purpose. The specific form matters less than the consistency.

The mystics did not agree about God. They did not agree about cosmology, doctrine, ritual, or ethics. They agreed about this: the separate self is not the whole story. And underneath it, everything is connected. And the name of that connection, in every tradition that has tried to name it, is something like love.

If that is the bedrock of what a human being is — not a theory, but an accessible experience — then this manual's central premise holds. Not as aspiration. As biology, as neuroscience, as the oldest knowledge the species has.

We are, beneath everything, one. The mystics found that out. The question is whether the rest of us will.

- Aldous Huxley, The Perennial Philosophy (1945) - William James, The Varieties of Religious Experience (1902) - Walter Stace, Mysticism and Philosophy (1960) - Andrew Newberg, How God Changes Your Brain (2009) - Roland Griffiths et al., "Psilocybin can occasion mystical-type experiences having substantial and sustained personal meaning and spiritual significance," Psychopharmacology (2006) - Rumi, The Essential Rumi (trans. Coleman Barks) - Meister Eckhart, Selected Writings (trans. Oliver Davies) - Ramana Maharshi, Who Am I? - Black Elk and John Neihardt, Black Elk Speaks (1932)