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THUAN: Since the sixteenth century, the place of humanity in the universe has gotten smaller and smaller. In 1543, Nicolaus Copernicus, a Polish priest, knocked the Earth off its pedestal as the center of the universe and discovered it was just another planet revolving around the Sun. Ever since, the ghost of Copernicus has continued to haunt us. If our planet wasn't at the center of the universe, our ancestors thought, the sun must be. But along came an American astronomer, Harlow Shapley, who discovered that our sun is just a suburban star among hundred of billions of stars that make up our galaxy. We now know that the Milky Way is only one of the hundred billion or so galaxies in the observable universe, which has a radius of about 15 billion light years. Humanity is just a grain of sand on the vast cosmic beach.
Human life has also become smaller in terms of time. Now we know that on a timeline that shows 15 billion years of the universe as one year, the first human appears only at 10:30 P.M. on December 31 (about 3 million years ago). Stonehenge is built and the Egyptian civilization arises at 10:50:54 (about 3000 years ago). The Buddha appears on the timeline at 11:59:53 P.M. (2500 years ago), and Christ shows up at 11:59:56 P.M. (2000 years ago). The European Renaissance occurs at 11:59:59 P.M. (450 years ago), on the last day of the year.
This shrinking of our place in the world led to Pascal's cry of despair in the seventeenth century: "The eternal science of endless space terrifies me". Pascal's words were echoed three centuries later by the French biologist Jaques Monod: "Man knows at last that he is alone in the unfeeling immensity of the universe, out of which he has emerged only by chance". And the American Steven Weinberg remarked: "The more the universe seems comprehensible, the more it also seems pointless".
Personally, I don't think that human life emerged purely by chance in an unfeeling universe,. To my mind, if the universe is so large, then it evolved that way in order to allow us to be here.
MATTHIEU: Careful, that sounds like what Bernardin de Saint-Pierre said: "Pumpkins have slices because they are made for family eating!"
THUAN: We must be careful about arguments based on justifications of final causes. Science was born from total and categorical rejection of any such teleological thinking, which is the province of religious doctrines. That said, modern cosmology has discovered that the conditions that allow human life seem to be coded into the properties of each atom, star and galaxy in our universe and in all of the physical laws that govern it.
The way our universe evolved on what are called "initial conditions" and on about fifteen numbers called "physical constants." Newton's law of gravity depends on one of these constants, a number called the "gravitational constant", which determines the strength of gravity's attraction. In the same way, there are other numbers that control the power of weak nuclear forces and the electromagnetic force. Then we have the speed of light and the Plack constant, which fixes the size of atoms. After that, there are numbers that describe the mass of elementary particles, such as the proton. the electron, and so on.These constants play a fundamental role in how a universe evolves. They determine not only the mass and size of the galaxies, the stars, the Earth, but also of living beings: the height of trees, the shape of a rose petal, the weight and size of ants, giraffes, and people. The reality we know would be quite different if the constants changed. As their name suggests, these constants do not vay in time or in space. This has been checked by careful observations of far off galaxies. As for the initial conditions of the universe, they concern, among other things, the amount of matter it contains and its initial expansion rate.
If these constants and initial conditions were just slightly different, then we wouldn't be here talking about them. The universe, right from the start, seems to have carried the seeds that allowed for the emergence of consciousness, of an observer. In the words of the physicist Freeman Dyson, "The universe in some sense must have known that we were coming".
MATTHIEU: The fact that our existence seems to be coded into each part of the universe shows how compatible we are with the physical world. But it certainly doesn't mean that you can say this is true because there was some intention that we should be here.
THUAN: Yes, but so far we haven't come up with a theory that explains why these constants were fixed at a particular value and not a different one. We've been handed these numbers on a plate and have to accept them.
MATTHIEU: Is there really no explanation for this?
THUAN: Leaving aside pure chance, which we shall come back to later, there is the superstring theory, which states that the elementary particles are created by vibration of infinitely tiny bits of strings. According to the theory, the mass and charge of a particle are determined by how the string vibrate. But this doesn't solve the problem, because the theory doesn't explain qhy the string vibrate one way and not another, or why they create particles with exactly the properties needed.
MATTHIEU: Could these constants be different in a different universe?
THUAN: According to our present state of knowledge, there's no reason why they shouldn't vary from one universe to another. By constructing a large number of "model universes" on their computers, astrophysicists have discovered that if the physical constants and initial conditions were just slightly different, then there'd be no life in the universe.
MATTHIEU: How much would they have to change by?
THUAN: The exact figure depends on which constant and which initial condition we're talking about. But in each case, just a tiny change would make the universe barren. For instance, let's take the initial density of the matter in the universe. Matter has a gravitational pull that couteract the force of expansion from the Big Bang and slows down the universe's rate of expansion. If the initial density had been too high, then the universe would have collapsed into itself after some relatively short time—a million years, a century, or even just a year, depending of the exact density. Such a time span would have been to short for the nuclear alchemy of the stars to produce heavy elements like carbon, which are essential to life. On the other hand, if the initial density of matter had been too low, then there would not have been enough gravity for stars to form. And no stars, no heavy elements, and no life! Everything hangs on an extremely delicate balance.
To give you an idea of just what small change I mean, consider the density of the universe at the start (or at Planck time). It had to be fixed to an accuracy of around 1060. That is to say, if one figure after sixty zeros had been different, then the universe would be barren. There would be no life, no consciousness. and no me and you to discuss it.This astonishing precision is analogous to an archer hitting a one-centimeter square target placed 15 billion light-years away, at the other end of the observable universe!
In the face of such extraordinary fine-tuning, many cosmologists have argued that the universe was so finely tuned in order to allow it to produce life, consciousness, and finally an intelligent observer capable of appreciating its beauty and harmony. This idea is called the "anthropic principle", from greek anthropos, meaning "person." According to this view, humanity has gained pride of place in universe once more—not at the center of the universe, but the very reason the universe is designed the way it is.
This is the "strong" version of the anthropic principle. There is also a "weak" version that doesn't presuppose any intention in the design of nature. It almost comes down to a tautology: "The properties of the universe must be compatible with the existence of humankind." The term "anthropic" is really inappropriate, because it involves that humanity in particular was the goal toward which the universe has evolved. But the arguments I've just presented can be applied to any form of intelligence in the universe.
Whichever of these versions of the principle one prefers, modern cosmology has, in this anthropic way of thinking, rediscovered a close link between humankind and the universe. Paul Claudel's message of hope answered Pascal's cry of despair and expressed this new delight with the world: "The silence of endless space no longer terrifies me. I walk through it with familiar ease. We do not live in some isolated part of a wild and hostile desert. Everything in the world is eternal and familiar."
MATTHIEU: As far as Buddhism is concerned, the idea that there is some principle of organization that is supposed to have tuned the universe perfectly so that the conscious mind could evolve is fundamentally misguided. The apparently amazing fine-tuning is explained simply by the fact that the physical constants and consciousness have always coexisted in a universe that has no beginning and no end. I don't mean that the universe is static. Rather I mean that what seems to be the start of the universe, the Big Bang for instance, is just one instance in an unbroken process. The conditions of our present universe harmonize with those of the previous and the subsequent ones, because the the process of causality is unbroken and entails a compatibility between the nature of the cause and that of the effect.
The universe has not been adjusted by a great watchmaker so that consciousness can exist. The universe and consciousness have always coexisted and cannot exclude each other. The problem with the anthropic principle, or any otherv teleological theory, is that it puts the constants before consciousness and thus claims that the constants exist only so that they can create consciousness. The anthropic principle comes down to picking up two halves of a walnut and saying, "It's incredible, it looks like these two pieces have been designed to fit perfectly together."
THUAN: I can certainly see that Buddhism has no need of an anthropic principle to explain life ans the conscious mind. But let's just suppose that the Buddhist view is invalid, and that it is, after all, necessary to explain the fine tuning of the physical constants and the initial conditions of the universe. We may then wonder if this tuning is the consequence of chance or necessity, to quote Monod's book. If we do not want to accept the anthropic principle—the argument from necessity —then we would have to turn to the other main argument cosmologists use to explain the fine tuning: the chance hypothesis.
This hypothesis postulates an infinite number of universes, and that each of these universes is constructed according to one out of all of possible combinations of physical constants and initial conditions. Thus for each combination of constants and initial conditions, a universe has once existed. But ours was the only universe born with just the right combination to have evolved life. All others were losers and only ours is the winner. If you play the lottery an infinite number of times, then you inevitably end up winning the jackpot.
MATTHIEU: When you say "other universes," do you mean parallel ones?
THUAN: That's one possibility. The idea of parallel universes is certainly one of the strangest one in physics. The idea depends upon one of the fundamental, and quite strange, findings of quantum mechanics. According to quantum theory, it is impossible to state precisely where subatomic particles are located. ...
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