The concept of Nonduality can be understood in several ways, but generally it involves the nonexistence of an individual self:
In the seen there is only the seen,
in the heard, there is only the heard,
in the sensed there is only the sensed,
in the cognized there is only the cognized:
This, Bāhiya, is how you should train yourself.
When, Bāhiya, there is for you
in the seen only the seen,
in the heard, only the heard,
in the sensed only the sensed,
in the cognized only the cognized,
then, Bāhiya, there is no ‘you’
in connection with that.
When, Bāhiya, there is no ‘you’
in connection with that,
there is no ‘you’ there.
When, Bāhiya, there is no ‘you’ there,
then, Bāhiya, you are neither here
nor there
nor in between the two.
This, just this, is the end of suffering.
~ Ud 1.10
According to the teachings on Dependent Origination (paṭiccasamuppāda) and Emptiness (Śūnyatā), all phenomena are conditioned, and thus, impermanent and without essence (or inherent existence). This includes all mental phenomena, particularly the personal self, or self-consciousness.
Consequently, most people will interpret nonduality to mean that there are only experiences and no individual experiencer, or just a series of experiences: “When, Bāhiya, there is no ‘you’ there, then, Bāhiya, you are neither here, nor there, nor in between the two.”
All this seems to make much sense, but for the fact that it is not possible to have an experience without an experiencer—even for a Buddha. This is because of the nature of human conscious experience.
Although the argument for the existence of just experiences (without a true being that has an experience), or as being Buddha Nature, is very persuasive, it is irredeemably contradictory. Buddha Nature referring to an all-encompassing pure awareness but without individuality.
You can state, for example, that in a very profound way an apple can exist and not exist at the same time. But this cannot be experienced because it is contradictory. In the same manner, you can say that you can have experiences without an experiencer, but as far as it is humanly possible, there has to be someone who knows that “it is an experience.” Experience without an experiencer is a contradiction.
Even people who are having hallucinations from illegal drug use, like as with mescaline, have an awareness of the hallucinations as an object of the pure awareness; otherwise, they would be unconscious of such an experience.
As well, you can say that Buddha Nature, or pure awareness, is not individual, but it cannot be experienced as such.
Consciousness is always a consciousness of something, which means that it is always directed at some object of consciousness. It is always a point of view, always a consciousness that sees something, that hears a sound, and that thinks thoughts. This is all that can be known (experienced). Everything else is speculation.
Experiences without an experiencer would be an unconsciousness and only occurs with the lower animals: being just pure awareness without self-awareness.
The philosopher Emanuel Kant (b.1724, d.1804), pointed out that we are only conscious of appearances, or the effect that “things” have on consciousness. We can never know what lies beyond the conscious experience itself, or what the “things” in themselves truly are.
For example, the red shape and taste of an apple result from the physical effect that object has on our nerve receptors and thereafter on their contact with consciousness. All the physical qualities of the apple are expressed as nerve impulses in the brain. In other words, we can never know what that object really is.
This also means that all experiences are made of consciousness. All we know is consciousness.
If this is difficult to understand, it is easier to demonstrate. Just close one eye and with your finger push the side of the open eye as you are looking at something. You will notice that the object you are looking at moves when you push the eye with your finger. This can only occur because the image is recreated from nerve perceptions and then projected in the mind–how else could the image move. You are never seeing the world directly, but only as it appears to you.
Kant also demonstrated in his master work, The Critique of Pure Reason, that the perception of cause and effect, and even of time, are also mind created.
This means that all that we know to exist, exists only in individual consciousnesses. It is in this sense that the conscious experience of an individual is nondual, as we can never know what exists outside our consciousness. All that we truly know to exist is conscious impressions. Everything exists in the human consciousness. What lies beyond is unthinkable.
Since everything is a conscious appearance, then everything is empty of any inherent nature. Everything is Sunyata, except for the pure awareness of Sunyata.
But then, what does the Buddha mean by, “there is no ‘you’ there”? How can this nonduality be understood?
What the Buddha realized is that the “you” (the “I”) is a creation of the mind made of thoughts and memoires. It is another object of the knowing consciousness, and as a result, empty of true essence:
Bhikkhu, ‘I am’ is a conceiving; ‘I am this’ is a conceiving; ‘I shall be’ is a conceiving; ‘I shall not be’ is a conceiving; ‘I shall be possessed of form’ is a conceiving; ‘I shall be formless’ is a conceiving; ‘I shall be percipient’ is a conceiving; ‘I shall be non-percipient’ is a conceiving. ~ M 140.31
The knowing consciousness, or the pure awareness, is what knows everything that exists as a conscious experience: as forms, feelings, perceptions, and consciousness of a self.
Pure awareness is the Unconditioned consciousness. The Unconditioned becomes conditioned when it gets mixed up with the things of existence and becomes the “I” and the “you.”
When the Buddha says “you do not exist” he is referring to the mundane “you” that is constructed from your thoughts and memories (which are objects of a consciousness).
When he says, “in seen there is only the seen,” he means to be aware of seeing, hearing, tasting, feeling, and thinking as objects of awareness, or without a reference to the self. It requires not desiring nor disliking things in respect to what they mean to you. Existence is just existence. It is the mundane self that gives it qualities, like pleasing or unpleasant, good or bad, beautiful or ugly.
We have access to individual pure awareness because this is what we truly are. This is the unconditioned. If pure awareness is not individual then there is no reason for human existence, no suffering, no Enlightenment, and no Buddhism. This is Nihilism.
In fact, Buddhism is not that complicated because it is not metaphysical. All you need to do is not get caught up with any desire or dislike for anything or anyone. You then meditate until you realize the existence of your pure awareness as not everything else (the Not-self Doctrine).
Buddhism becomes more difficult, in fact almost impossible, when you think of it as a metaphysical doctrine instead of a practical one. That is, when you start thinking about what exists and what doesn’t exist.
The Buddha often insisted that all he taught was the cause of suffering and the end of suffering: the Four Noble Truths and the Eightfold Path. Following his teachings brings about wisdom and lasting peace of mind.
The following is a talk by the late Thai Buddhis monk Ajahn Chah. He was renowned for his down-to-earth but deeply penetrating wisdom.
When the mind transcends conditions, it knows the unconditioned. The mind becomes unconditioned, the state which no longer contains conditioning factors. The mind is no longer conditioned by the concerns of the world, conditions no longer contaminate the mind. Pleasure and pain no longer affect it. Nothing can affect the mind or change it, the mind is assured, it has escaped all constructions. Seeing the true nature of conditions and the determined, the mind becomes free. . . The tendency to conceive things in terms of self is the source of happiness, suffering, birth, old age, sickness and death. This is the worldly mind, spinning around and changing at the directives of worldly conditions. This is the conditioned mind. . . We should clearly understand these determinations. Good, evil, high, low, black and white are all determinations. We are all lost in determinations. . . If we know the truth of determinations clearly, we will know that there are no beings, because ‘beings’ are determined things. Understanding that these things are simply determinations, you can be at peace. . . This is true merit, to be calmed of proliferations, calmed of ‘being,’ calmed of individuality, of the burden of self. Transcending these things one sees the unconditioned. This means that no matter what happens, the mind doesn’t proliferate around it. ~ Ven. Ajahn Chah, ‘Toward the Unconditioned,’ in ‘Food for the Heart.’
The Unconditioned mind is just your pure awareness, pure knowing. It is pure because it knows but does not need anything it knows. It is marked by simplicity and peacefulness.
Every individual is originally a point of view of pure awareness. In this sense, we are all Buddhas in the making.
If I were to ask Ajahn Chah, or the Buddha, what is your Nibbana, what is your pure awareness, there would only be silence, because any words would be just ideas, representations, and not the experience itself. Or perhaps they would say, “it is not anything that you can think about.”