Science in search of a Worldview

Piet Hut

Here follows the text of my presentation at the Mind and Life meeting in Dharamsala, in 1997, together with the discussion that took place during the presentation; it was published in 2004 in the book The New Physics and Cosmology, ed.: A. Zajonc [Oxford University Press], p. 196.

Piet Hut: I am delighted to be here today, and this whole week. I was very happy already on the flight from New York to Delhi, because I saw this picture in the newspaper of the very things I study. It's a photograph taken with a normal optical telescope, of two colliding galaxies. I am going to show you the same thing happening in my computer simulations of imagined galaxies, but it is nice to see the real thing here. You see a very complicated pattern of light, with two tails of light going out in different directions. We think that these are two galaxies that had a traffic accident. Because of the high speed of the collision, some of the stars were pulled off in these tails. We did not know that these were collisions until thirty years ago. Before that we thought they might be very strange galaxies, perhaps born that way. But thirty years ago, computers began to be fast enough to simulate the history of a collision.

What you see here is a picture of the same type of collision taken from the Hubble space telescope from outer space. Because there is no air, you can take much more beautiful images than you can from the ground. Not only do you see there is a collision, but you see gas clouds in the galaxies colliding and new stars being born because of the high pressure. Each of these many bright lights is a new star or a group of new stars.

Dalai Lama: Do the stars actually collide with each other physically, or is it simply an interpenetration without actual collision?

Piet Hut: The stars don't hit each other. They are very small compared to the enormous space in between. So, two galaxies can pass through each other, although they still distort because they feel the gravity. But in between the stars there are big gas clouds, and these clouds collide.

Dalai Lama: What happens to the direction of the motion? Is there any indication that one will pull the other in its direction?

Piet Hut: If they go at high speeds, they go through each other. They are a little bit slowed down but they keep moving.

Dalai Lama: When these new stars are formed, do they ever form their own autonomous organization as a new little galaxy, or are they always dragged off by one or the other colliding galaxies?

Piet Hut: That's a very good question and both can happen. If you look carefully, you see that in these arms there are some bright spots where new stars are born. They will form small galaxies, child galaxies which will leave the main galaxy.

At high speed two galaxies pass through each other. At slow speeds they just stick. At intermediate speeds they don't pass through completely, and when they fall back they become one galaxy. That is what happens most often.

If you would like to see whether they go through or stick, you have to wait a few hundred million years. Most of us are not so patient, so we ask the computer what will happen. I will show you an example of a simulation.

Dalai Lama: In that time, chances are that an individual could get enlightened and be able to tell the whole story of what happens to the galaxy.

Piet Hut: So, there is a competition between science and enlightenment.

Computer Simulations as Valid Inference

Piet Hut: These are two galaxies at time zero. The time is measured in units of one hundred million years. Both of these galaxies, the blue and white, indicate the presence of the stars. The red light indicates dark matter, the invisible mass that we know is there because we can feel the gravitational pull. If you look through a telescope, you see only what is colored blue or white here, in the form of galaxies, shaped like pancakes. Let's see what happens when they meet each other.

So, you see the tails were similar to those in the photograph. The whole process, which you saw in a few seconds, took four hundred million years in reality.

Dalai Lama: This is mathematically calculated? Is it more than sheer speculation?

Piet Hut: Oh yes. For each step of three million years, we calculate the gravitational force from each point to every other point. We have more than ten thousand points, so for each step we calculate a hundred million forces. Actually, we cheat. At the start here we add many forces together and compute them in one step instead of calculating them all separately. You do not have to get it absolutely correct. It is good enough to calculate the basic forces, but the mathematical equations are one hundred percent accurate. The initial positions are the only question. We try many different initial positions until we get something that looks like what we see. It's like going into a forest for only one day to find out how trees grow. You can count the tree rings and think about it, but you only have one day to look at the forest. We only have one day in the cosmos, a very short time for analysis.

Dalai Lama: I wonder if a simulation like this would be considered a genuine inference in terms of Buddhist epistemology. Genuine inference is real knowledge based on reasoning, where you can be very, very confident to an extremely high degree of probability that it is true. Is that the case, or is this an informed guess?

Piet Hut: I would say it is a good approximation. As an approximation it is very secure, but it is not secure for all the details. There are small aspects of gas clouds, or magnetic fields, or other things that we do not know.

Dalai Lama: Are these events taking place within the region of the afterglow?

Piet Hut: The afterglow is radio radiation everywhere in the background, throughout the universe. It comes from far away for everybody. The afterglow is like the light of the sky, and these galaxies are like birds flying in front of the sky. The sky looks far away. Its light, if it travels to our eyes, is nearby, but it comes from far away. In the past, the whole universe was glowing, and after it stopped glowing the light kept traveling.

To show how the universe expands, we have to start with one little piece of it-several galaxy clusters-and watch it get larger. What you see is that the original gas in the universe forms small galaxies and gas clouds, and those galaxies and gas clouds fold together to form groups of galaxies. This is how structure in the universe is made. Each point of light that you see is not one star, but many, many stars.

Dalai Lama: Is there a typical number of galaxies within a standard galaxy cluster?

Piet Hut: They come in all sizes. Our local galaxy group is small. It has two big galaxies, ours and another one, and about ten or fifteen smaller galaxies. But nearby is a much bigger group, and we are part of the next hierarchy, a meta-group of thousands of galaxies.

Dalai Lama: A poetic text by Nagarjuna asks, if the earth, mountains, ocean, and stars all eventually become mere dust, what cushion is there left for us weak mortals? What immortality can we expect? Even the galaxies dissolve. Astrophysicists should make this point especially to the politicians, and to those people who are killing each other over religion?to what purpose?

Piet Hut: If we could get radio signals to other planets and astronomers could talk to each other as ambassadors, maybe we would have a better universe. But we have to wait a bit for that.

I very much enjoy playing with these simulations. As a child, I enjoyed playing with model railroad trains. When I grew up, my toys grew up, and now I play with galaxies.

Anton Zeilinger: What's the next step then?

From World Systems to World Views

Piet Hut: Maybe now I have to play with world systems, or perhaps world views. The nice thing is that I even get paid to play with these galaxies, but I also do some other things on the side. One of those is that I am very interested in the whole question of world views-views not only of the physical reality, but of the world as a whole, including human beings and their sense of beauty and meaning.

In a dialogue between science and Buddhism, or more generally between science and religion, people talk about building a bridge. You mentioned recently that Nagarjuna says that many metaphors are only partly correct. I think that the bridge metaphor is partly correct, but I do not like it very much. I think the real meeting point happens when we go down into the canyon, to the roots where the knowledge of science and of Buddhism come from, to this lesser known area. In America, where you need slogans because Americans have very short attention spans, I call this 'roots, not fruits.' That means a focus on the process, not the results or the fruits of science and Buddhism. It is very interesting to talk about the Big Bang, or about Buddhist and Christian equivalents of the origin of the world. But even more interesting is the process of knowledge formation, of the development of wisdom and of compassion. Maybe in science in the future we'll be able to talk about that process of knowledge.

If we want to go to the roots of science and religion, as a scientist of course I have to start on the side of science. I would like to show you my view of the roots of science. I first have to look at the structure of different forms of science, at their relationships, and the process of how they grew. Sometimes people use the metaphor of the house of science, with mathematics on the first floor, and physics, which is based on mathematics, above it on the second floor. Biology uses physics and chemistry, and these are like higher floors in a house. Mathematics itself is based on a particular logic. I have made the foundation of logic, below the first floor, smaller because there are a limited number of logical rules from which a large body of mathematics and physics extends. As a result it looks more like a stupa than a house, but that's okay in this environment.

There is a reductionist tendency in this model-a tendency to explain life by looking at DNA, at the physics or chemistry of molecules and atoms. Similarly, if people study the brain in psychology, they look at the biological structure of the brain, at the nerve cells and how nerve signals propagate. Each level is explained in terms of a lower level, from psychology, down to biology, down to physics, down to mathematics, down to logic. Scientists as well as people outside science often talk about science by starting with principles. There are scientific principles, such as objectivity, repeatability, and consensus between scientists, which then lead to logical, mathematical laws. Everything else rests on top of that. The outcome of biology and psychology is, for example, knowledge of the body and the brain, and more and more knowledge about experience-how human experience arises from the brain, from the embodied being, starting with the simple elements.

This seems to be the structure and the process of science, but I think this picture is misleading. It is too simple. It is an ideal, but in practice what happens is that new discoveries sometimes force us to modify the principles. In physics, for example, it is true that at any given time logic determines how to do the mathematics, and mathematics determines the physics, there are these relationships between the levels. But new discoveries like quantum mechanics force us to change the first principles, to start with new principles to explain what is happening.

Dalai Lama: Historically in Buddhism it is as if physics were to come first and a formulation of logic were to come later. Buddhist logic was strictly formulated in the fifth century by Dignaga and then reformulated in the seventh century by Dharmakirti, and Buddhism was long established before that. It's interesting to consider what the basis of logic is. The law of the excluded middle, for example, is based on a kind of experience. As we look around and see how things happen, on the basis of that experience we start to formulate logic. The logic wasn't made in a vacuum. It was an embodied logic to start with, which we draw out from experience. Then the logic comes around and defines and clarifies further experience.

Piet Hut: It's very similar in physics now.

Thubten Jinpa reports on a side conversation that took place between himself and His Holiness in Tibetan:

Thubten Jinpa: I was arguing that logical principles, such as identity, contradiction, or the law of the excluded middle, have a lot to do with the way human thought functions. They are based simply on the tools with which thought operates, and they are fundamental assumptions without which we just can't make sense. His Holiness took the opposite position, saying that these are principles abstracted from the physical world. For example, the quantum phenomenon of superposition suggests that there may be a need to modify the Buddhist logical position that the law of the excluded middle applies in all instances.

Dalai Lama: If logic really isn't coming simply from an a priori position, disengaged from nature, but is based upon nature, then you have to modify your logic as new information comes in. Buddhism must modify its logical principles based upon the new empirical evidence coming in.

Piet Hut: I think physics has to change much more than Buddhism. David has expressed some very interesting ideas about the need to change to a quantum logic. It is a very exciting topic.

What you just said about the historical origins of Buddhist logic reminds me that this house of science began to be built very recently, only four hundred years ago in Europe. They had inherited the logic and mathematics of the Greeks. That was already at least two thousand years old. But the Greeks were only talking about static things. Then Galileo and Kepler discovered the physics of motion. It was clear that to understand this new physics, such as the detailed motion of the planets, we needed to modify the mathematics and the logic used for their description. Newton invented a new mathematics for very small intervals-in principle, for infinitely small intervals-to be able to describe arbitrary shapes. Newton investigated the first modification of mathematics based on principles from physics. People thought that after Newton, there was no further need for change. This was dogma until quantum physics.

Of course, this classical framework is still correct to a high degree, but if you do very precise experiments, you have to modify it. So, it is still very useful, but not entirely accurate. In quantum mechanics, for example, you cannot exactly repeat something, such as the time taken by a radioactive atom to decay. Three hundred years ago the most important thing in physics was repeatability. If you could not repeat something, you could not verify it. That really was dogma, a cornerstone of science. The strange thing about the building of science is that it is like a floating house: you can change the ground floor or the basement while the rest of the structure still stands. It's not entirely true that psychology has to be based on biology, and biology has to be based on physics; if it were true, then modifying the principles of the foundation would cause everything to collapse. But that does not happen. Biology has its own understanding, and even if you change physics, it will continue. There is no reason to believe that this process of feedback, leading to modification of principles, will not continue. Just as physics has led to new mathematics, I expect that biology or psychology will lead to new physics, and make the foundation richer.

Dalai Lama: Are you talking here about empirical psychology?

Piet Hut: Yes. Empirical first, and then theoretical deductions follow from the empirical results. Theory and experiment always go together. Theory alone is dogma. Experiment alone is mute. You do not even know how to describe an experiment if you don't have the language of theory to talk about it.

Other examples of modifying principles show that the general tendency is not arbitrary. There is consistent pattern. It always moves in the same direction, namely from absolute to relative. If we learn something new, we first think, 'Ah! I have found the truth.' Then we learn more, and we think, 'Mmm? Maybe it is not absolute. Maybe there is another side to it.' We don't throw it away, but we place it in a larger context. In physics, we have even called such developments 'relativity theory,' as in Einstein's relativity theory. But calling a theory a relativity theory is a negative way of saying it. A more positive way would be to call it a transformation theory.

Transformation Theory

Piet Hut: One of the simplest relativity theories is kitchen relativity, where you can transform water into ice. You can freeze water or melt ice. If you grow up on a tropical island, you don't know ice, you only know water. Water is absolute; you never see anything else. But one day you go travel, or you get a refrigerator, and you can transform water into ice. Then you see that water is relative. Ice also is relative, but the material seems to be absolute, since you can transform in either direction. It is the same material, but with a different appearance, a different form. The relativity of water and ice gives you more freedom. It gives you the freedom to make a transformation. You can do more things than you could before. Similarly, Einstein's relativity showed us that space and time are not absolute, but you can transform them to some extent into each other.

Dalai Lama: In the case of ice and water, you simply had different manifestations of form and the same substance. Is it really so closely analogous when you speak of time and space? Does time actually transform into space, and space actually transform into time?

Piet Hut: It is a close analogy in the sense that normally, what is space from one point of view is space with a little bit of time taken into account from another point of view. Likewise what is time for me, will be mostly time with a little bit of space mixed in for you. This only becomes significant at very high speeds.

Dalai Lama: It looks like simply two corollary changes taking place-this changes, therefore that changes-rather than an actual transmutation of a body of space into a unit of time. However, the substance of the water actually turns into the substance of the ice and vice versa.

Piet Hut: Actually you can make a complete transmutation from space to time. But you can only do that inside a black hole.

David Finkelstein: There is no symmetry at all between time and space. You were correct when you said that space enters into time, but doesn't become time. Time enters into space, but doesn't become space. It's as if you could transform a pitcher of water to a pitcher of water with a little bit of ice in it. But you can't go all the way.

Piet Hut: I would argue that time and space reverse roles with respect to a distant observer. But let's talk about that off-line; it is a rather technical point.

David Finkelstein: Going back to the example of the railroad trip, if I make a round trip I have moved in space and time. From another person's point of view, I moved only in time. We can have a transformation of time into time and a little space, but never time into space.

Piet Hut: What can transform completely are mass and energy. You can have mass completely transform into energy, and energy completely transform into matter. A nuclear bomb and a nuclear reactor are examples. That follows from the space/time transformation. If you study the mathematical theory of Einstein's relativity, you see that space and time transform at least to some degree, and that mass and energy transform fully like water and ice.

Dalai Lama: We have a lot of illustrations even in the macro-world, of mass turning into energy. It happens in the fireplace. Can you give an example of energy transforming into mass?

Piet Hut: You can see it happening in elementary particle processes. A photon is transformed into two material particles: an electron and an anti-electron. Material is produced from pure energy, from a photon.

Dalai Lama: Does this happen only at the microscopic level?

Piet Hut: It happened with the whole world after the Big Bang. After the Big Bang, everything was energy in the form of radiation. When it got colder, the radiation condensed into matter, like steam condensing into droplets of water.

Dalai Lama: But it does not happen as a day-to-day event in the macro-world?

David Finkelstein: When a plant absorbs solar energy, it gets a little bit heavier.

Piet Hut: Yes, in principle, but by a very tiny amount.

Dalai Lama: How can you have energy all by itself without some material basis for that energy? Likewise, can you clarify how a photon has no rest mass, but when it's in motion, it does have mass?

Piet Hut: The problem is that you could say the photon is a type of physical material. So the modern view sees a photon as a form of matter. A hundred years ago, people said that light is pure energy, and this table is pure matter (knocks on table). Before relativity theory, there was a duality between matter and energy. But now that we know they are similar things.

Dalai Lama: How can you have energy just standing all by itself, without a material source?

David Finkelstein: There's no such thing. Energy is always a property of something else.

Dalai Lama: If there is no such thing as energy standing all by itself, what does it mean to say that energy transforms into mass?

David Finkelstein: I think we have to say it correctly. Your Holiness is finding logical errors in our ordinary way of speaking. It's always simply a transformation of one form of energy into another. It's just a very old-fashioned way of thinking that mass is turning into energy. Turning mass into energy is like turning pounds into ounces. It's the same stuff. There's energy in this cup, but it's bound into the nucleus. They are exactly the same thing; they differ only in units.

Anton Zeilinger: I would disagree with that because I have to define things operationally. What do I mean by mass?

David Finkelstein: You can measure both mass and energy with exactly the same instruments. That's Einstein's discovery. You can weigh energy, and you can measure mass with a kind of thermometer, a calorimeter. They are the same stuff. It's not even a transformation-just a liberation, a change in form.

Anton Zeilinger: You're right. You can weigh energy.

David Finkelstein: Matter is not the same as mass. Radiation is not the same as energy. Radiation is a cloud of light particles. It has energy, just like it has color. Energy is one property of it.

Piet Hut: The confusion is because we started with one understanding a hundred years ago, and we continue to use the words derived from that understanding. Now we have a new understanding, but we still use the old words.

The reason for the confusion about the rest mass and moving mass of a photon is this: If an object moves, some of its energy is the energy of motion. Much of its energy is mass, locked up in the material, which could, in principle, be released in a nuclear explosion. If I want to find out how much mass, it's hard to know if the object is in motion. I have to stop it and carefully weigh or analyze it. The problem is, if you stop light, it disappears. You cannot stop light. In a photon, all of the energy is in the motion. There is no energy locked up. A photon is manifest energy. A physical object has hidden energy.

The Role of Experience in Science

Piet Hut: In our picture of the house of science, we saw that scientists normally cheat and tell you only part of the story. They do not often tell you that they rebuilt the foundation. Another thing you do not hear about very often is even more fundamental: the filter that separates experience from the construction of science. For me this is extremely important, and it is almost always left out of academic discussions.

Dalai Lama: By filter, do you mean exactly which aspects of general experience we will filter out and which we include as part of science?

Piet Hut: Yes. The primary and secondary qualities are an example. Three hundred years ago, people determined that the length of an object is physics, but its touch and color is subjective. Human beings can feel the object and can see the color. But in physics we only talk about mass, length, and time. Color has not been interesting for physicists. Now we have a much more detailed understanding of matter, and we have modified the filter: now we can compute the color of materials. Our filter is getting larger and we can describe more.

Dalai Lama: But even now in physics when you speak of color, you are talking about photons and such things. As Arthur pointed out with his study of Goethe's color theory, you're still leaving out what we actually experience as color, or sound and so forth.

Piet Hut: Subjective experience does not go through the filter. Beauty and responsibility and meaning do not go through, at least not at the moment.

Dalai Lama: Does mind go through?

Piet Hut: Not as subjective experience. When scientists talk about experience from the standpoint of psychology and biology, they are focusing on the body and the brain. While this 'experience' comes from the real experience, it leaves out much. Then they make an abstract picture using mathematics and physics. They build up to biology and then they reconstruct the experience. There is no reason to believe that it works completely. It is only an approximation.

If a neuroscientist tells you that he or she knows this or that about experience, or if a biologist claims knowledge about human brains from evolution, specific conclusions may be right. We have a lot of detailed knowledge. But there is no reason to believe that we have the complete picture. Probably we do not, because so much is left out and the knowledge structure is constantly changing. But as the filter is being modified, then hopefully our understanding of experience is improving and getting more accurate.

What I think is most interesting about science is the notion of freedom from identification. In this century, we have seen that the old picture of the world of objects that we see around us really has to be replaced by an interplay of interactions. Every phenomenon is an interaction. Everything we know about the photon is given as a play of actions. The photon can sometimes play as if it is more like a wave and sometimes it plays more like a particle, depending on which question we ask. We cannot identify it uniquely saying an electron is a wave or is a particle. It is more fluid; there are more possibilities. Using our understanding of different roles, we have to see that the roles are only roles and not definitive, not absolute. Therefore, at least in physics we can see that we really need to give up identification.

Dalai Lama: By identification do you mean the notion of thingness?

Piet Hut: Yes. Identification of any fixed thing is one example, but also any property. It's like the elephant. You cannot identify it with a leg or with a tail, or with any specific set of parts. The change from objects to actions, or from objects to phenomena, can be considered as a change from 'is' to 'as'. An electron is not a piece of absolute substance. But an electron can appear as a particle, or as a wave. It can play a certain role. One way of saying it very briefly is to say 'nothing yet there' or 'non-existing it appears.' I really like that expression. I think that this truth was discovered on a very fundamental level much earlier in your tradition than in the scientific tradition. I do not think it is a coincidence. I think it tells us something about the fundamental structure of reality on the level of the roots, not the fruits.

Dalai Lama: It can't be a pure coincidence that both science and Buddhism come to more or less the same conclusion on the nature of emptiness when taking physical objects as the focus of analysis.

Piet Hut: In principle it could be a coincidence, but only if the physical world and the mental world are absolutely different without any possibility of transformation. But I think that we need to look at possible connections between relativity and transformation. And if they are connected, then I do not think it is a coincidence.

As an example, we talked yesterday about the Big Bang in physics and space particles in the Kalachakra system of Buddhism, and it is very interesting to compare those two. Some aspects will be similar and some may be different because the results are determined in part by the method of investigation. However, I think the logic is most fundamental. If you really understand the logic more and more, at some level the ground has to be similar. If it is not the same, we have to go deeper to find the connection. Somewhere the canyon must have a bottom that connects both sides.

Already I think science has found a high degree of freedom from identification. The question is, where are we going in future? I can only see that we are moving from a science of objectivity to a science that includes subjectivity as well as objectivity. The next relativity theory or the next transformation theory will include a relativity between the object and the subject, between the physical and the mental.

Dalai Lama: It's getting more encompassing and vaster. For a long time my intuition has been, that up until now the domain of science has been rather confined in being limited to the physical world, focusing only on what can be quantified. Gradually science will have to expand its horizons so that it can bring into its domain of analysis phenomena that may not be subject to quantification like physical objects. From what you have shown us, I feel you may share the same hope.

Piet Hut: I have the feeling I am climbing down from science's side into the canyon, and the deeper I go the more I can see the other side. I cannot jump yet. I am a little bit too scared to make such a big jump, but from here I can see the Tibetan notion of the sameness of outer and inner space-that they are not really something different. I recognize the language from the other side, and I see in it something very similar to what I expect to happen in the language of science in the next hundred years or so. The search for a wider view, a wider context, a wider space-that is what science will soon investigate in much greater depth. It would be very nice to look at Buddhism and see whether we can get some help. In the beginning it was very difficult to help each other. We were too far away at the top of the canyon, but now we are getting closer. It is more and more possible to learn from each other at the level of the underlying logic and processes.

Between Illusion and Reality

Arthur Zajonc: Piet, could you amplify one of points that you have raised, about the play of actions? You talked about how, through increasing relativity, we free ourselves from the tendency to identification and reification of the world of object, focusing instead on a play of actions. One of the dangers here is that the language you used suggests whimsy, that it is a mere play of appearance or actions, as opposed to something that has content or meaning. There is an analogy in relativity theory, in that space and time considered independently are illusory. Here also it is not the case that they are just playful appearances. There still is a deep structure, but the structure is at another level. Could you say something about this middle ground between objectification and complete relativism?

Dalai Lama: I want you to continue but let me add something. The Madhyamika Prasangika view posits a form of knowledge that can also have an aspect of illusion in it. One can establish valid cognition even though appearances have an illusory quality or aspect to them.

Within the Buddhist epistemological discourse, there are two divergent opinions. Some maintain that any form of valid knowledge must be valid in relation to all aspects of the object, which implies a belief in some kind of intrinsic being of the object of perception. This is a classic correspondence theory, with a real world out there corresponding to valid cognition. However, the Madhyamika Prasangika view argues that there is no need to attribute a true being to the object and, also, there is no need to assert that knowledge is valid in relation to such a true being. One can talk about an illusory knowledge. From the other point of view, the discussion of interplay or appearances immediately suggests hallucinations and pure illusion. But once we are able to accept the notion of valid cognition that may have an illusory appearance, then there is no danger of misinterpretation when we talk about appearances and mere play.

Piet Hut: You gave a very nice example a few days ago, about looking at a flower-that if you believed the flower was really there you could appreciate it in one way, as substantial. But if you realize the flower is not substantial, then you are even more free to appreciate the flowerness of the flower without having this fixed identification. I think there is a similar aspect here of freedom from identification-not having to grasp, but just appreciating the phenomenon and the structure in the phenomenon.

If physics changes the rules of the game, it can change the principles and the filter, but physics does not have the power to change the experience before subject/object analysis. Insofar as you want to talk about reality, that non-dual experience is most real, most given. There was a mathematician in America who asked his students if they really believed that by changing set theory, for example, they would cause the bridges built on the basis of that theory to fall.

Dalai Lama: Whatever transmutations physics and the other sciences may go through, however they may redefine themselves, reality stays as it is.

Arthur Zajonc: Is experience dependent upon the observer? Is it necessary to have an experiencer in order to have experience?

Piet Hut: I would say that, within the field of experience, there is the appearance of an observer and the appearance of the observed. The observer who has experience and the experience that has an observer are interdependent.

Dalai Lama: There are two terms for experience in Tibetan. Perceptual or direct experience [lengay] means the natural, spontaneous, raw perceptual experience that you are born with. Kundop means something conceptually structured or fabricated. That doesn't mean it's fallacious, but it is more conceptual, derived from a great deal of highly theoretical investigation. This latter emerges as a domain of experience that would not have occurred without all of that research, investigation, and conceptualization.

Piet Hut: Looking from science, I would add that there are filters. In addition to the filter that science places on experience, there are other filters in our educational system, in our childhood, in our culture, in the way our innate experience is molded into a shape. For example, we believe in subject/object organization. The subject/object split is deep down inside us, before it appears in science. My answer to Arthur's question is that deep down, it is non-duality. The subject and the observer are part of the totality of experience.

Dalai Lama: Are you suggesting that starting from raw cognition, valid and invalid, you could go through training and research, until finally the process of science brings you to valid cognition? That is, in fact, what is sought in Buddhist meditative training. You start out with a lot of confusion and false assumptions, but you go through a discipline, and as a result of that discipline, you end up with valid cognition. Are you suggesting something comparable here?

Piet Hut: From the point of view of science, the situation is still very confused. Science is making progress, but it cannot say anything yet about the original raw experience. Science can look at what Buddhism has to say about this experience and can get inspiration from Buddhism, but science can also continue on its own, modifying the principles and enlarging the filter. All we know is that the future wider scientific framework will look very different than the present one. The present physics looks very different from the one we had a hundred years ago, and a hundred years later, I would guess, it will look very different again.