What science tells us about reality
The history of Western science is well-documented, reaching back to Greek thinkers whose names are still remembered today: Aristotle, Pythagoras, Archimedes, Euclid, Democritus.
With the publication of Sir Isaac Newton’s Principia in 1686 CE, science gained a major new paradigm. What has come to be called Newtonian mechanics was created by many people, and it proved to be a powerful way of looking at the world.
In the Newtonian universe, matter was held together by forces, and energy moved in waves though fields. Each behaved according to a fixed set of laws, which we could discover through theory and confirm through experiments. The universe was vast and fixed, with galaxies bouncing off each other like billiard balls on a pool table.
Cause and effect was a fundamental law, where every action has a opposite and equal reaction. You couldn’t get more out of a process than you put in.
Energy could neither be created nor destroyed, only changed. Energy also and always flowed from areas of greater energy to areas of lesser energy, like air escaping from a balloon. Scientists called this property of energy entropy, and some said it would cause the universe to one day be lifeless and cold.
Darwin’s theory of evolution roughed up the perfectly ordered world of Newtonian mechanics by introducing chance and evolutionary change that was far more complex than the laws of chemistry or motion. Later Darwinian thinking came to picture humans as a product of an eons-worth fight for survival of the fittest. It made humans realize that the human species was the result of a process in time that could be measured in geologic ages.
Scientists knew that a chemical process could be charted over time, but in Newtonian mechanics, time was a variable independent of space. You could follow a process backwards and forwards. And in mathematics you could reverse time and still define the equation as true. This led to thinking that time itself might be reversible.
The scientific methods of theory, experiments and results were applied in many fields. When Sigmund Freud applied them to the human psyche, he shattered the idea that the mind was a single place.
A spectacular success
Science was a big hit right off the bat. In a few hundred years, science created locomotives, steam engines, telephones, cars, and much, much better standards of living.
Science declared it couldn’t talk about anything it couldn’t measure, so the reigning religious paradigms made an uneasy alliance with it, fearing that science might one day try to measure God.
Newtonian mechanics sank deeply into human culture. It is so much a part of modern culture that we use the terms like cause and effect every day. Scientists today regard Newtonian mechanics as a perfectly good tool for many things. But it is not accurate for everything, not after Albert Einstein discovered relativity in the early 1900s.
Einstein’s contribution was so great that it defined the start of a new way of thinking. Special Relativity declared that energy and matter were the same, that matter was in fact made of energy. Human culture is still trying to catch up with the idea.
General Relativity was even more revolutionary. Space and time are not separate, but are joined. What we thought of as a gravitational force is a curvature of space-time. As Stephen Hawking notes in A Briefer History of Time,
Space and time are now dynamic qualities: when a body moves or a force acts, it affects the curvature of space and time – and in turn the structure of space-time affects the way in which bodies move and forces act. Space and time not only affect but also are affected by everything that happens in the universe.
Beyond simple cause and effect, Einsteinian physics describes a weave of space-time in which everything affects everything else.
An expanding universe
Einstein himself believed for a long time that the universe was vast, but fixed in size. He even introduced a variable into his equations called the cosmological constant that was just enough matter to keep the universe a constant size.
Astronomer Edwin Hubble discovered that the universe is actually expanding. Hubble measured the light from distant stars and found them to be red-shifted. A red-shift in light occurs when the light is moving away from you, and Hubble found that all the galaxies were moving away from us, implying that the universe is expanding. He also found that the farthest galaxies were moving the fastest, which means that the universe is not only expanding, but is accelerating in its expansion.
When scientists went looking for the reasons, they found light coming from background cosmic radiation. Working backwards, the light tells us that the universe that is describable by general relativity exploded in all directions 13.7 billion years ago.
It has been expanding and evolving ever since.
While general relativity explored the universe, another set of scientific insights about the very smallest level of reality was being organized.
It began with the discovery that there were very small packages of energy, called quanta, that had properties quite different from larger structures. Because of the limits of measurement, using even a quantum of energy to perform an experiment would affect the quantum state of the object. This means that observation affects the experiment to such a degree that you can never be certain of completely defining anything.
The recognition of uncertainty has led in interesting directions. Quantum physicists see life as a set of probabilities. For large objects, the probabilities are very high that they exist in one physical state. For very small objects, the probability that you will find a particle or a wave depends on which one you are looking for. Instruments that look for particles find particles. Instruments that look for waves find waves.
The subject and object are linked enough for the subject to pick up the object from the quantum foam, the state of energy that exists as a wave just underneath the most elementary particles we can find.
After the Big Bang
No one knows what conditions were like before the Big Bang, though there are interesting theories based on how physics must have been different. You see, the Big Bang and the moments afterwards established a very specific set of parameters for the physical nature of the universe. A set of parameters so highly specific that probability cannot begin to explain why our universe contains life. The universe is so specific to life that Stephen Hawking says in The Grand Design that
…calculations show that a change of as little of 0.5 percent in the strength of the strong nuclear force, or 4 percent in the electric force, would destroy either nearly all carbon or all oxygen in every star, and hence the possibility of life as we know it. Change those rules of our universe just a bit, and the conditions for your existence disappear!
Hawking goes on to say:
The emergence of complex structures capable of supporting intelligent observers seems to be very fragile. The laws of nature follow a system that is extremely fine-tuned, and very little in physical law can be altered without destroying the possibility of the development of life as we know it. Were it not for a series of startling coincidences in the precise details of physical law, it seems, humans and similar life forms would never have come into being.
What can we make of such startling coincidence?
Quantum physics doesn’t know. The best it can do is suggest that since all things are uncertain in quantum theory, every possibility exists.
Why some possibilities happen and not others can be learned from modern thermodynamics.