This is the second part of the Question Beyond Science exploring how certain we can be about what we think we know. Yesterday’s post discussed certainty and religious belief. This post asks whether science can provide us with absolute certainty. Again, your feedback is warmly welcomed.
How the Scientific Method Works
The scientific method is in many ways a highly disciplined application of the kind of reasoning processes humans use all the time.
First, we experience something – we see the sun come up in the morning, for instance, and set every evening. In a scientific study, this is what is called “data.”
Then we ask what it means, we try to explain it. How it is, for instance, that the sun comes up every morning and sets every evening? In science the explanation is the “theory.”
But science adds several qualifications to these steps. The first isreplication of the data. Scientists agree that data must be subject to being checked by other scientists. So scientists study only objects and events that other scientists can also observe if they choose. Whatever a scientist studies, from the stars to how people behave, the basic requirement is that other scientists can also observe and analyze it.
This is to rule out errors or fraud or even hallucinations or dreams that are mistaken for something objectively real.
The second qualification of science is in relation to theory. Science neither accepts nor denies the existence of a supernatural world. It does, however, look for explanations solely within the operations of the natural world. So even if a scientist believes in God, it would not be an acceptable scientific theory to hypothesize, for instance, that the sun is under the control of a god who takes the sun away at night and brings it back every morning.
It is because science insists on data which is observable and theories which are rooted in the laws of the natural universe, that its theories can betested.
How Theory becomes Fact
A scientific theory is first developed as an explanation for something we observe. It is then tested by examining its predictions. The more predictions made by a theory which are correct, the stronger a theory becomes. Each correct prediction contributes to its proof.
For tens of thousands of years, human beings looked at the data and concluded, quite reasonably, that the world was flat. Very few people questioned what seemed to be obvious to almost anybody who had ever walked on it. But about 500 years ago, Copernicus suggested not only that the world was shaped like a huge ball but that it was twirling around in space and at the same time whirling around the sun. This was a whole new explanation which at first sounded preposterous.
How did we all become convinced not only that it wasn’t preposterous but was actually fact, was, in other words, true? We became convinced because the theory predicted and explained so many other things that it began to make sense.
This new theory explained how it was that the sun seemed to set at night and come back again on the other side of the sky in the morning. It explained the changing positions of the stars. It explained why the seasons regularly changed from winter to summer and back again. It explained how ships sailed around the world and got back home without ever turning around. It explained so many things that people now say it’s not “just a theory,” but a “proven fact.”
By a similar process, Newton’s theory of gravity, Mendel’s laws of heredity, and Darwin’s theory of evolution have become “fact.”
But scientific facts, no matter how much proof backs them up, never become absolutely certain. They may be accepted by most people for a very long time under most conditions, but scientific facts are never beyond question.
Why?
How Can a Fact that is Proved be Disproved?
Facts are disproved when the theory that explains the fact is no longer accepted. The “fact” that the world was flat was disproved when the theory that earth was round was accepted. The “fact” that the sun went around the world was disproved when the theory that the earth went around the sun explained things better and so was accepted by scientists and by most people.
Newton’s theory of gravity that said the universe worked like a gigantic clock is no longer accepted as fact since scientists have shown that the force of gravity isn’t strong enough to hold the world together. The “facts” that parallel lines never meet, that a mile is always the same length, and a minute lasts just as long no matter where you are have been disproved by Einstein’s theories of relativity.
Many of these disproven facts still work quite well in our small world where we still walk on what seems to be a flat world, where the sun still comes up and goes down each day, where a mile is always 5280 feet long, and a minute always 60 seconds.
But they are not absolute facts because time and space a relative. So they aren’t certain no matter what. No matter what the “fact,” there is always the possibility that another theory will convince us that what we thought was indisputable is not certain after all.
So although science has taught us a lot about the universe, science always deals in various levels of uncertainty. Some levels of certainty are very high. But it is not absolute.
What do you think?
Are there some things about which you think you can be absolutely certain? Why or why not?
Is your certainty about scientific fact and religious belief different?
Copyright © T. Herman Sissons, Ph.D.
Penrose’ theory explains why there are clearly visibly variations in the rings surrounding some galaxies.
