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Our future, our universe, and other weighty topics


Tuesday, March 10, 2015

If You Had Always Lived in a Random Universe

Humans seem to take for granted any law of nature that regularly acts to their benefit, no matter how wonderful such a law may be, and no matter how improbable such a law may seem from the standpoint of random actions of material particles.

To illustrate this point, let us imagine a different universe. In this universe there is a most amazing law called “the law of soft collisions.” So in this alternate universe, whenever anyone jumps out of a tall building, or falls from a high cliff, their speed starts to decrease at just the right time, causing them to gently land without suffering any damage. Also, when two cars travel directly towards each other at high speeds, their paths always divert at just the right time so that there is no hard collision. (Please do not test whether this “law of soft collisions” works in our universe; I can assure you that it does not.)

If people had always lived in such a universe, would they regard this “law of soft collisions” as some evidence that their universe had been carefully designed? I think very many of them would not. Instead, they would simply take the law for granted – just as we take for granted the laws that make our existence possible. In such a universe we might see conversations such as the following.

Physics teacher: So, to review our lesson for today, it is a fundamental law of nature that nothing can ever collide violently. We call this “the law of soft collisions.” So, for example, when people jump out of skyscrapers they always land softly and safely. And there has never been a death from an automobile collision. And when people fire bullets at other people, the bullets always swerve away from their targets or slow down, so that no harm is ever done.
Student: My dad says that the “law of soft collisions” is so convenient that it may perhaps be a bit of an indication of some purpose or plan behind the universe.
Physics teacher: Sentimental nonsense! The “law of soft collisions” is simply the way that nature has always worked, a “brute fact” that we can no more “explain” than we can explain the laws of mathematics.

Returning to our universe, do we ever take for granted any laws that are as seemingly providential as this “law of soft collisions”? Yes, we do that all the time. The laws we take for granted are the laws of nature that make our existence possible. These laws include: the laws of nuclear physics that bind together protons and neutrons to become an atomic nucleus, the laws of gravitation that allows large bodies to form, the laws of electromagnetism that allow complex life to exist, the Pauli exclusion principle that makes solid matter possible, and also certain laws of quantum mechanics that allow the existence of atoms by making sure that electrons do not fall into the nucleus (something they would otherwise have a natural tendency to do because of the electromagnetic attraction between protons and electrons).

We inevitably take all of these wonderful things for granted, simply because they are part of the fabric of reality as we have always known it. It is hard for us to imagine any other reality. But suppose we try really hard to imagine a completely different reality. Let us make such an attempt, by trying to imagine what it would be like if you had always lived in a truly random universe.

In a truly random universe, there would be no convenient laws that cause matter to organize into galaxies, stars, planets, and atoms. So at first glance it seems impossible to imagine yourself living in such a universe, because biological life would be impossible. But let's get over this difficulty by cheating a little. You can simply imagine yourself as a disembodied spirit or energy floating around from place to place.

What would life be like for you in this utterly random universe? We cannot imagine you living in a house, or walking on the ground, because there would be none of the favorable laws of nature that make possible planets and solid matter. But you can at least imagine yourself floating around like a misty cloud drifting in the wind.

What kind of matter would there be around you in this random universe? There would be only disorganized matter drifting about. The closest thing in our universe to such matter would be the disorganized matter that drifts about in a gaseous nebula like the one shown below.


Occasionally such drifting matter might form into interesting random concentrations, although nothing too interesting because of the lack of gravity. But you would not be able to appreciate even these mildly interesting concentrations of random matter. This is because there would be no sunlight or starlight anywhere in your random universe. Sunlight and starlight both requires stars, and stars require many favorable laws and some fine-tuned constants, which would not exist in your random universe.

So you would not be able to see anything in this random universe as you drifted randomly from place to place. For you there would be no home, no solid matter, no beauty to appreciate. You would be like some blind cloud drifting around in a moonless night sky, being tossed around by dark, random forces. Life would be very, very dull.

Now let us imagine that after living many years in such a blind, drifting existence in a dark random universe, you suddenly found yourself transformed into a material being standing on the surface of a solid planet. If you then learned about the laws that made possible this orderly material universe, you would have the greatest appreciation for such laws that you had only just started to experience, regarding them as numinous marvels infinitely more amazing than having a huge monarch butterfly drift through your open window every day of the summer.

But we can never have any such appreciation ourselves. We instead will always utterly “take for granted” whatever favorable laws exist in our universe, no matter how improbable or providential they may be.