We begin with a narrow question: what is the simplest possible description of nondual experience – the essence that most established traditions refer to?

David Loy’s 1988 book – Nonduality: A Study in Comparative Philosophy – offers a starting place. His project is to show how nondual traditions of Advaita Vedānta, Mahāyāna Buddhism, and Taoism, despite their disagreements, essentially allude to the same thing.

Loy’s approach is comparative. He studies these traditions side-by-side, finds the essentials they commit to, and notes where they agree and disagree.

We should note that “nonduality” is not confined to these traditions, and these traditions have no special authority. But they are among the oldest, most established, and most influential instances of nondual reports and philosophy. Their ideas can be triangulated to find common ground.

Phenomenal vs Metaphysical

For our purposes (not Loy’s) – one distinction is necessary:

A phenomenological claim describes what someone’s experience is like from the inside: “I felt totally absorbed in the music.” A metaphysical claim says what reality is for everyone: “we are all part of one consciousness.”

The trouble is that “nondual” experiences often arrive with a feeling of truth attached, and descriptions often leap from “phenomenal report” to “metaphysical doctrine” in the same sentence.

While Loy examines metaphysical claims, we exclude them for two reasons. First, this is where the traditions diverge, and we are looking for agreement. Second, and most importantly, metaphysical claims aren’t necessary for grasping the experiential nature of nonduality and its implications for everyday life.

Here are examples of common metaphysical claims:

• Consciousness is fundamental / primary – the ground of reality, that from which matter and world derive.
• All is one / There is one universal consciousness – a single mind or awareness that everything is part of.
• The world / matter is illusory (māyā) – physical reality doesn’t really exist; only awareness is real.
• Universal mind is God / Godhead – consciousness is divine intelligence.

Any such claims are unnecessary for our inquiry.

If any terminology feels strange or hard to understand, hang in there – nonduality is counterintuitive by nature. We’ll summarize everything in the simplest possible terms at the end.

What Is Nonduality?

“Nonduality” is used loosely by many people to describe many things. Loy’s first chapter distinguishes the three most common cases:

The negation of dualistic thinking. Our concepts come in opposed pairs – good/bad, being/nonbeing, success/failure, pure/impure – and the pairs are interdependent: each term is only intelligible relative to its opposite, so affirming one quietly maintains both. (The practical version: a life organized around purity is a life preoccupied with impurity.)

The nonplurality of the world. Drop the “representational overlay” (explained in the next section) and the world stops presenting as a warehouse of discrete, self-standing objects. What the traditions call Brahman, Dharmakāya, or Tao is, at minimum, this: the world experienced whole rather than parsed.

The nondifference of subject and object. The deepest part of the representational overlay is the sense of a self – a subject standing apart from what it experiences. A whole world isn’t whole if the experiencer stands outside it surveying it. So the deepest claim is that seer and seen are not two. Loy describes this as one of the most “striking and counterintuitive” claims in philosophy, illustrated with a quote from Plotinus:

“There were not two; beholder was one with beheld; it was not a vision compassed but a unity apprehended”.

The Core Nonduality Theory

Loy assembles what he calls his core theory:

The world can be experienced two ways. In the dualistic mode, it shows up as a collection of discrete objects (one of which is “me”) interacting in space and time. In the nondual mode, the same world shows up undivided, with no experiencer standing apart from it. The bridge between the modes is superimposition: the dualistic world is the nondual world with a representational overlay.

One Experience, Four Interpretations

At this point, we must grant that “experiencing the world in nondual mode” is possible, meaning, perception can feel like some unified experience and a sense of self fades.

Even if the reader cannot imagine this, it isn’t necessary to show how such an experience can be interpreted.

Imagine four people having this experience and describing it:

(These are short characterizations of actual philosophies. Don’t worry about understanding their exact meaning.)

Person 1: two things are real. There’s the awareness, and there’s the stuff happening in it – and these are utterly different kinds of things, forever. The watching never becomes the watched; the sky never becomes the clouds. Reality is a pure witness on one side and everything else on the other, and freedom is telling them apart. That’s the dualistic account of Sāṅkhya-Yoga.

Person 2: only the space of awareness is real. Think about it – the weather comes and goes, but the sky was there before, during, and after, unmarked. Whatever comes and goes can’t be the real thing – whatever never comes or goes must be. So the aware space alone is real – unborn, unchanging, without a single feature – and all the happenings are just appearances it puts on, the way a screen puts on a movie. That’s the nondual account of Advaita Vedānta.

Person 3: you’ve got it backwards – only the happenings are real. A space with no features? Something with no color, no shape, no location, no qualities at all is not a subtle presence – it’s nothing. What actually shows up, moment to moment, is just the events themselves: this patch of red, this sound, this thought — not a flower (that’s a label), and not an “I” watching the patches (that’s a label too). Just the arisings — with, surprisingly, a deep peace where the “I” used to be. That’s the nondual account of early Buddhism.

Person 4: you’re all doing the same thing wrong. Each of you took something from the experience and promoted it to a “thing” that really exists. The first made two things, the second made the space a thing, the third made every little event a thing. But nothing in the experience stands on its own; everything leans on everything else, so nothing qualifies as ultimately real. That’s a nondual account of Madhyamaka.

One experience – four incompatible interpretations – each fitting the experience perfectly.

We can read this divergence as something subversive: While the nondual experience is real, it is describable in mutually incompatible ways. Which one is true is a question the experience never answers. The disagreement between the traditions is the strongest evidence that exact interpretations were never the important part.

What have we learned?

If anyone wishes to understand nonduality, consider that these traditions (and many others) are littered with conflicting metaphysical claims and dogma that muddy the water. This means at best they are partially true. Rather than pick one, there is an entirely different option:

Cultivate the experience, and let it speak for itself.

But how?

Meditation: Disarming the “Representational Overlay”

Returning to our “core theory”, there are two ways to see the world. A nondual world, and a dualistic world, which is a view of the nondual world with a “representational overlay”.

What is this representational overlay and how do we disarm it?

The book’s second chapter shows how training our attention is the gateway, and why meditation is the relevant instrument – not merely a mood-regulator or relaxation aid, but a technology aimed at quieting this representational overlay.

In ordinary perception, the overlay is invisible: a patch of color is never experienced as a patch of color – it arrives pre-packaged as a cup, an object, out there, mine. Some hidden mental process shows us the cup and builds a sense of ownership. Buddhism, for example, points to the alternative: train the mind so that “in the seen there will be just the seen; in the heard, just the heard.” William Blake puts it like this: “If the doors of perception were cleansed, everything would appear to man as it is, infinite.”

The objection here is obvious: perception is always laced with concepts!

Nobody hears “pure noise” – for example – we hear a motorcycle. Loy concedes – and cites Gregory (psychologist), and Popper (philosopher) who show ordinary perception as automatic and need-driven. For example, a hungry animal sees the world as food. But then he shifts the question: the representational overlay is automatized, and what is automatized was once learned, and what was learned can, in principle, be unwound.

Meditation, on this account, is precisely the unwinding.

In the psychologist Arthur Deikman’s term, de-automatization – “the undoing of automatization, presumably by reinvesting actions and percepts with attention.” Sustained attention with no task, no need, no point of view is the one condition under which the representational layer, built to save attention, has nothing to do – and thins.

Deikman conducted two small concentration studies from the 1960s, in which all subjects, over repeated sessions, sat in a room and focused on a vase. After a long enough period, subjects reported the vase’s properties changing:

The color of the vase shifted to a deeper and more intense blue, frequently described as “more vivid.” “The adjective ‘luminous’ was often applied, as if it were a source of light.” “It was as if light were coming from it.” “It started radiating. I was aware of what seemed like particles…[that] seemed to be coming from the highlights there and right at me.” Another effect was an instability in the shape of the vase. Its size and/or shape changed; it appeared to become two-dimensional; and there was “a diffusion or loss of its perceptual boundaries.” Often the vase appeared to move: “rocking,” “drifting,” “wavering.” “The outlines of the vase shift. At that point they seem almost literally to dissolve entirely…and for it to be a kind of fluid blue…a very fluid kind of thing…kind of moving.”

The changes were not confined to the vase. Deikman’s own summary notes that the alterations ran “in the direction of fluidity and breakdown of the usual subject-object differentiation.” One subject described it directly: it felt “as though the blue and I were perhaps merging.” Another, gazing out a window after a session, reported “I wasn’t watching myself watching” – the antithesis, he said, of being self-aware.

Notably, these shifts were temporary, and could not be summoned on demand. When Deikman’s subjects tried to repeat an experience, the trying itself interfered with the concentration that allowed it in the first place. The representational overlay quiets when attention rests – and reasserts the moment the shift becomes the goal. Nondual perception, on this evidence, is not a switch that stays flipped. It comes in glimpses.

Deikman’s thread has since been picked up: the adjustability of the self/world boundary is now an active research program, from predictive-processing models of meditation to neuroimaging studies of meditators dissolving the sense of self.

What does all of this suggest?

What the studies establish is narrow but remarkable: the representational overlay is adjustable. The larger suggestion is that nondual perception is not some exotic attainment bolted onto the mind. It is what perception already is, when that learned overlay goes quiet. No study can settle this. It is checkable only in the first person, in meditation practice – and it requires no metaphysical position whatsoever.

Why Bother? Peace. Wisdom.

Loy’s conclusion turns to values, and here we focus on two points.

Some suffering is produced by the representational overlay, and that suffering can disappear when the overlay quiets. Loy puts it through Spinoza: blessedness is not the result of virtue but virtue itself – “the other side of this is that suffering is not the punishment for evil, but evil itself. The essence of our duḥkha is the sense of separation.” Trimmed of metaphysics, the claim is modest and testable: a baseline of peace is available that does not need to be manufactured, because it is what remains when attention rests. Loy illustrates it this way: “life is nothing but a series of such timeless experiences: a sip of coffee, a few words with a friend, a walk down a path” – and someone who cannot trust the world enough to forget himself into such moments “condemns himself to watch his life ooze away.”

The second benefit concerns everything we don’t control – which, on inspection, includes most of the mind. Loy’s chapters on action and thought converge on one finding: thoughts and intentions arise on their own, no orchestrating self is discoverable behind them, what we call the thinker is assembled after the fact. His conclusion draws the consequence in a sentence that reframes the entire problem from a war of will against unwanted contents to a question of how clearly the contents are seen. Practically: once the mind is seen to run itself, its productions lose their automatic authority. They can be engaged, declined, or left alone – related to, rather than obeyed or fought. The peace of the first benefit funds the discernment of the second: from a settled baseline, it becomes obvious how much of what the mind serves up was never worth entertaining, and how much of life was spent entertaining it. That recognition reaches further than it first appears – into identities and long-held aims, not just passing moods – and it accumulates. Nothing here happens in a single glimpse – it is many glimpses, metabolized over years. The book’s word for the transition is liberation. We can describe it more humbly: a durable shift in what one takes seriously.

Summary: What Is Nonduality?

Let’s return to our question:

What is the simplest possible description of nondual experience?

When Loy scans the traditions for overlap, this is the gist:

The world can be experienced two ways. In the dualistic mode, it shows up as a collection of discrete objects (one of which is “me”) interacting in space and time. In the nondual mode, the same world shows up undivided, with no experiencer standing apart from it. The bridge between the modes is superimposition: the dualistic world is the nondual world with a representational overlay.

How can we experience nondual mode? Turn down our representational overlay.

How can we turn down this representational overlay? Attention and meditation.

Why would we do this? When we see so much of our mind (thoughts, feelings, assumptions, narratives, impulses, self) arises on its own, we don’t have to take it personally. In everyday life, we can engage with our mind more carefully.

Before: I feel this. I think this.

After: Here is a feeling. A thought. Are they true?

An Anecdote

I started meditation practice in 2020. My intentions were simple. Explore my mind and see what I find. I meditated 4-5 times per week, starting with guided meditations, then on my own, for about two years.

I consider myself fortunate, because “nonduality” was not a target I was aiming for. Instead, I was simply meditating and taking stock of subtle changes over time.

Sometimes this change was during meditation. For example, noting the inherent peace when I stopped paying attention to all the clutter in my mind.

Sometimes this change was outside meditation. For example, watching myself getting distracted with things that didn’t really matter, and removing worries from my life that were wasting time.

Eventually, this culminated in some very vivid experiences. For example, out of the blue one day, I thought about the nature of desire, and how the happiness that comes from so many kinds of desire is fleeting. Or in another example, I was looking around at all the objects in the room, and realizing I was experiencing a mural created inside my perception, NOT the actual “objective world”.

The point being, as the months passed by, my “representational layer” was flickering on and off, giving me glimpses into nondual perception, and thus, impacting how I relate to myself, the world, and how I want to be.

This is approximately three years of my life distilled. It was not some “mega moment” of insight. It was a slow background practice of meditation and contemplation, and small insights, which gradually shifted perspective. Only later, searching for similar accounts, did I explore this landscape of nonduality more deliberately, and attempt to reconcile with what I had been experiencing.

What I learned: hold nonduality descriptions lightly. Beware of unjustified metaphysics. Most of all, cultivate these experiences for yourself with meditation and contemplation.

Resources

This article distilled what nonduality is according to major traditions – and the high-level approach to cultivate nondual perception – but did not provide specific tools. On that end, here are some places to start.

• The Waking Up App – A mindfulness meditation app. Start with the introduction course, and wander to lectures, talks, discussions.
• Mindful Glimpses – A mindfulness app that works with “pointers” or “glimpses” – short instructions designed to quiet the representational overlay.
• Why Buddhism Is True – Not an endorsement of Buddhism, but a tour of how so many aspects of Buddhism seem “true” – as witnessed by a non-Buddhist.
• Self-Investigation.org Discussion Forum – An online community to discuss this material and experiences.