A reductionist approach to science has become so ubiquitous that many scientists find it difficult to imagine that science can be done in any other way. Interactions among elemetary particles are the ultimate explanation, the only final cause. Biology can be reduced to chemistry. Chemistry is the science of large numbers of atoms, interacting according to the laws of quantum physics.
But reductionism is only a habit of the way we do science. It is logically possible that there are global laws, interconnections, entanglements; and that these are discoverable by investigation that is rigorously scientific . Teleology is commonly dismissed as "unscientific", but it is precisely teleology that we may need to explain a host of diverse findings that conventional science has swept beneath the carpet.
One of my oldest friends is a professor of computer science at a great mid-western university. An Israeli-American, Uri is descended on his mother's side from an ancient line of Kabbalist mystics, but his philosophy is strictly materialist. He believes that "the mind is what the brain does", that the brain is a computer, and that electronic computers can be programmed to do anything that our brains can do. Like a great majority of computer scientists, he believes that subjective consciousness is something that arises when computation attains a certain kind of complexity.
Last summer, Uri told me a story from his youth. In college, he had dated a young woman, a passionate political activist. Years after he had lost touch with her, she sunk into depression with the election of Ronald Reagan. Uri awoke one night, sweating and screaming, from a nightmare in which she had jumped from a building. Though he had not talked to her in several years, he reached out and tried to contact her the next morning, and her parents informed him she had killed herself that very night, jumping from the window of her apartment. Uri was shaken at the time, but he has filed the experience in his memory as a coincidence, a curious anecdote with no particular message about the way our world works.
Sitting in a canoe, listening to Uri's story, I asked him if he thought an artificial intelligence might ever have such dreams. What would he think if his story and many like it were collected in a stastical database, and it could be demonstrated that such "coincidences" were far too frequent do be dismissed, that their composite probability was far rarer than "five sigma" (roughly "one chance in a million"), which is a conventional threshold for announcing that physics has discovered a new particle. He responded thoughtfully: He didn't have time to do that kind of analysis. It depends on so many people's stories, and people's memories of such things aren't so reliable. But if it could be established, he said, he would be forced to conclude there were new sub-atomic forces that brains can use to communicate, and that physics had not yet discovered. In any case, he was committed to the idea that reality is physical -- space, time, matter and nothing else -- and that every phenomenon of nature must be explainable in reductionist terms. By definition.
How Science came to be narrow-minded, with universal ambitious
Don't doubt the Creator, because it is inconceivable that accidents alone could be the controller of this universe.
-- Isaac Newton
Newton's scientific ambition was prodigious. He first conceived the idea that the universe was governed by precise mathematical laws that were independent of place and time. But he never imagined that physics was a completepicture of the world. It was only in the 19th Century that the idea took hold that physical law might explain everything. Science had been enormously successful in accounting for diverse phenomena, expanding again and again to explain more of our world. Then scientific philosophy made an audacious leap: Every phenomenon in our universe is regular. All of our experience can be accounted for in terms of deterministic mathematical laws.
Is this statement true? We all assume it is. But in fact, it is an empirical statement, a bold one, to be sure, and all the more reason it should be challenged and tested experimentally.
Of course, it's not literally true that two experimenters doing the same experiment always find the same result. There's experimental error--mistakes and misjudgments that enter any human enterprise. And in biology, there is the complication that no two organisms are exactly alike. These things were understood and accounted for in the Nineteenth Century. This was the time when "vitalism" was stripped out of biology, and living things were boldly assumed to depend on the same mechanistic laws as non-living matter. Biology was conceived to be built upon chemistry, and chemistry could be understood as the interactions of atoms. It was at the level of atomic physics that the Universal Machine operated in a manner precisely determined by mathematical laws.
But 20th Century science shattered determinism. The Scientific World-view retreated just far enough to allow for quantum randomness and the Heisenberg Uncertainty Principle.
"Philosophers have said that if the same circumstances don't always produce the same results, predictions are impossible and science will collapse. Here is a circumstance that produces different results: identical photons are coming down in the same direction to the same piece of glass. We cannot predict whether a given photon will arrive at A or B. All we can predict is that out of 100 photons that come down, an average of 4 will be reflected by the front surface. Does this mean that physics, a science of great exactitude, has been reduced to calculating only the probability of an event, and not predicting exactly what will happen? Yes. That's a retreat, but that's the way it is: Nature permits us to calculate only probabilities. Yet science has not collapsed."
-- Richard Feynman
To Einstein's consternation, God does play dice with the world. When the Twentieth Century discovered quantum indeterminacy, most philosophers of science made the minimal modification to their deterministic picture. To them, the future state of the universe is determined by its present state plus pure chance. In this paradigm, there is nothing outside physics, or if there is such a thing as "soul" or "spirit" or "free will", it is irrelevant to science and to experience. It can have no observable effects, because the physical universe is a closed system, governed perfectly by a combination of deterministic laws and pure chance.
This is the philosophy of "materialism" or "physicalism" that has become synonymous with the scientific world-view today. But it is far more explicit than the original scientific world-view, which says only that our knowledge of the world depends on empirical observation plus mathematical logic. In fact, the original scientific world-view is a system for discovering truth, but it is silent about what that truth ought to be. This expanded scientific world-view is not just a statement about methods, but contains a description of the nature of the world. It is a scientific theory, in the sense that it says something about the empirical nature of reality. Like all scientific theories, the expanded scientific world-view can never be proven true, but it can be falsified by observation.
The original scientific world-view as bequeathed to us by the Enlightenment is an epistomology which we can accept or reject, but no arguments can be adduced for or against it. The expanded scientific world-view is a statement about the world, and we may legitimately ask, "Is it true?"
The issue of reproducibility is the crux of the matter, and it is related to science in two ways.