The Other I

April 7, 2010

How certain is scientific fact?

Filed under: Questions beyond Science,Uncategorized — theotheri @ 12:53 pm

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 is replication 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 be tested.

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.


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.



  1. Just read this and the previous one on Certainty: religious belief and scientific fact. I found myself thinking that juxtaposing or comparing scientific belief and religious belief can leave someone with one of two overall conclusions.

    One is that because scientific certainty is unattainable (and a scientific ‘fact’ or theory is only true until it has been falsified), scientific belief is not so significantly superior to religious belief that religious belief is invalidated. They are both partial, both approximations to the ‘truth’.

    The other possible conclusion is that there is still a world of difference between them. Science packaged along with the methodology & philosophy of science constitutes a sound body of belief, which is no more certain than it ought to be, as it comes with its own health warning. People might be dismayed to learn that science is not as certain as they thought it was, but the gain from this learning is ultimately huge. Science may not hang together as an irrefutable network of truth, but it does hang together as a sound body of belief plus an explicit methodological basis for itself.

    Science may not hold out even the promise of ultimate certainty. But I think it does hold out the promise of coming to a completely sound understanding of what it is saying and what right it has to say it.

    It is this which I think religious belief profoundly lacks. It is certainly possible to apply analytical thought to religion. But in a completely ‘no holds barred’ analysis the religious content itself can evaporate and turn into something else, like philosophy or ethics.

    I’m not claiming this will necessarily happen. It will depend on who is doing the analysing. But it can happen, eg if the analyst is comfortable about losing the specifically ‘religious’ content.

    I don’t think it can happen with science though. As an approach, as a methodology, science is rock-solid, because it is its own most powerful adversary. There are good scientists and bad scientists, but science in itself is constitutionally modest. Religion cannot dare to share that modesty, because unlike science or philosophy or ethics there is no guarantee it will survive every demolition job it could inflict on itself.

    That’s my tuppence worth for tonight!

    Thanks again,
    thinking makes it so


    Comment by Chris Lawrence — April 9, 2010 @ 9:13 pm | Reply

    • I’ve been thinking about your suggestion that it is the methodology of science that gives it its credence, and I began to wonder about the “methodology” of religion. Religion, of course, doesn’t have a formal methodology of its own, and if one tried to fashion one, it would undoubtedly not apply to all religious doctrine equally.

      With that qualification in mind, it nonetheless seems to me that what religious leaders today often call “discernment” is the method by which religious truths are identified most often. This obviously leads directly to the problem that becomes unsolvable when different religious thinkers “discern” contradictory truths. It took 1800 years, but I suppose under these circumstances the emergence of the doctrine of papal infallibility was ultimately inevitable.

      A parallel difference between religious and scientific analyses is that each begin with different assumptions. Both, up to a point, must begin with some universally accepted but unproven assumptions. A critical assumption of most (but not all) religions is that there is another world above and beyond the natural world in which we live, and that decisions made in this other world can explain what happens in this world. Science does not accept that assumption. That will lead to an awful lot of critical errors by science if there is a power of this magnitude which science completely disregards.

      On the other hand, if the “other world” is no more than a figment of wishful thinking, then science represents a giant leap forward for human thought.

      Thank you for your thoughts. As you can see, for better or worse, they added once again to my own.


      Comment by theotheri — April 12, 2010 @ 9:32 pm | Reply

      • Thanks .

        Discernment: there’s a word to chill the blood!

        I’m sure you’re right that science, like religion, also rests on some universally accepted but unproven assumptions. But you don’t give examples. What did you have in mind?

        Reason for asking is to test my assertion that science is methodologically trustworthy, even if we can’t take its statements as certainties.

        Thanks yet again,
        thinking makes it so


        Comment by Chris Lawrence — April 13, 2010 @ 5:34 pm

  2. I fear that my last comment to which you have just responded was too eliptical to be clear. My excuse is that we have finally had some sunny weather and I have been spending every day light hour I can grab in the garden. But by the time I sit down at my desk, I’ve moved into whatever speed is the one directly above Full Stop.

    But as a result of your question, I’ve begun to think that differences in several basic assumptions between science and most religions might provide some fruitful insights into why the two approaches so often find themselves mutually incomprehensible. In fact, inescapably incompatible.

    So I’ve decided to write a full-fledged post on the subject.

    (Don’t say you didn’t ask for it.)

    Seriously, thank you for asking.

    Yes, I agree that “discernment” is indeed a word that chills the blood. At least mine. Very few other words leave me quite as speechless.


    Comment by theotheri — April 14, 2010 @ 7:16 pm | Reply

  3. Excellent article but I don’t know that I agree. Then again, folks consider me tricky at the best of times! Many thanks.


    Comment by — February 24, 2013 @ 2:48 am | Reply

    • Thank you for your comment. But tell me why you aren’t sure you agree! I don’t want to argue or even try to convince you — what I’m interested in most of all is how you see this question of science and religion. “Tricky,” I’m sure you will agree, doesn’t explain a lot about your thinking — though I would like to see you on the cycle.


      Comment by theotheri — February 24, 2013 @ 2:52 pm | Reply

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