In the historical dimension, there is still discrimination between birth and death, and this and the other. But when you go deeper, all these notions just disappear and you touch the nature of no birth and no death, no coming and no going, no being and no non-being. You are free from all notions. And that is nirvana. That is the state of coolness. Nirvana, the philosophical term, the spiritual term has come from the daily talking of the presence. In the morning, when you make a breakfast for your husband, you should gather some sticks in order to make fire. And the fire of yesterday may have died completely, so when you touch the ash, it's cooled and does not burn your finger anymore. So, nirvana is the state of coolness, not burning.
And the Buddha used the word, Nirvana, to talk about the state of no afflictions. Because afflictions like anger, fear, despair, they are burning us. They make us suffer. When we are able to remove all these afflictions, we are in the state of cooling. Nirvana is cooling, the cooling down. Because afflictions like fear, anger, despair, they are burning, that is why we suffer. And why we have these afflictions? Because of our way of looking at the world. Because we have notions of fear. Because we have notions of birth and death, being and non-being, me and you as separate entities. We use our mind of discrimination. We are caught by many notions, including the notions of subject and object, matter and mind. That is why afflictions arise. Once we are able to remove all these notions, including birth and death, being and non-being, and then all these afflictions have no cloud in order to be born and we are free. So, nirvana is freedom. And first, freedom of notions.
And in order to reach nirvana, you can not use your mind of discrimination. And the modern science begins to see that. There are scientists who say that quantum mechanics is dealing with nature as she is. And that is absurd. She is absurd. Quantum mechanics is dealing with nature as she is. It means absurd. Because we thought that it is here, it can be both here and there. We thought that it is wave but it may be something else like particle. Why? Because we are using a kind of mind. That can not touch the ultimate. In classical science, we have notions and ways. We believe that the reality can be independent from our mind. Whether we are there or not, nature is the same. Maybe in modern physics, we don't think like that anymore. We think reality is a function of mind. Mind is linked with reality in such a way that you can not take mind out of reality and you can not take reality out of mind. And modern science begins to see that object and subject, they can not be taken apart. They inter-are. Without this, the other one can not be.
So, the mind that we use in the historical dimension is called in Buddhism the discriminative mind. The Chinese word is "分別智". It's good for classical science. But it's no longer good enough for modern science. The Sanscrit word is "vikalpajnana". "jnana" means wisdom and "vikalpa" means discrimination. The mind of discrimination. We have to distinguish with between birth and death. Birth and death are two different things. We have to distinguish between left and right. They are different things. A rose is a rose. A rose can not be clouds. A rose can not be the sunshine. And our discriminative mind is based on the principle of identity. A can only be A. (A=A) A rose can only be a rose. A rose can not be something else. A human being can only be a human being. A human being can not be a plant or animal or mineral. And that is the mind of discrimination. And with that mind of discrimination, we can not touch the ultimate dimension.
And that modern science begins to see, to feel it. And that is why using the mind of discrimination, they find nature absurd. And that is why in Buddhism, we should use another kind of mind in order to approach the ultimate dimension, in order to touch nirvana. But the ultimate dimension is not something apart from the daily life. What we touch in the historical dimension contains nirvana. And you touch them deeply enough, and then mind of non-discrimination, and then nirvana is available in the here and the now. You don't have to go and look for it elsewhere. And that kind of mind is called the "nirvikalpajnana". The mind of non-discrimination. And when you train yourself to use that kind of mind, you don't suffer anymore because you can touch the ultimate dimension. You touch the reality as it is. And no longer are mental constructions.
The reality in the historical dimension for ego (separate self) is the relative truth, conventional truth. It's not too much to say that Albert Einstein explained it through his theory of general relativity. Albert Einstein's theory of general relativity is the principle in the historical dimension based on the duality. On the other hand, the reality in the ultimate dimension is the ultimate truth which transcends the duality. It is nirvana based on the non-duality. Only awareness (Buddha nature, Divine nature) can dwell in the ultimate dimension which has no space and time. That's because awareness is nature, not matter. Awareness can dwell in the phenomenal world and in the noumenal world at the same time because awareness transcends the space and time. If we (ego) attain the full enlightenment, awareness revives and we (awareness) can live in mindfulness 24 hours a day and will never return to ego (separate self).