What is Science: Is Science about Observation or Falsification?

By: Bruce
January 20, 2011

In previous posts I responded (or gave other people’s responses anyhow) to the ideas that science is primarily about prediction, Reductionism, or Holism. In those ideas we found some truth, but not the whole truth.

Another common point of view is that science is really about observation. Related to this is the idea that science is primarily about empirical evidence or in other words must be falsifiable. As it turns out, these points of view are somewhat correct, but also misleading.

Science is Not Primarily Observation

I doubt science would have any meaning if we didn’t take the ideas of observation and empirical evidence seriously. Descarte is rumored to have tried to argue in favor of pure reason, but we know that this doesn’t work out in real life. The problem is that our reasoning capacity is too broad. We can think of logical possibilities that just happen to not exist.

In a past post (in the notes) I hinted at one of these: Cartesian Dualism – the idea that minds and matter are different things and that minds can exist without matter. (Seemingly contradicted by D&C 131:7). I can conceive of Cartesian Dualism, but all the evidence currently points against it. Plus Cartesian Dualism is a classic violation of Occam’s Razor. It only provides explanations by pushing the problems it purports to solve to a new location plus creating new ones. (This does not rule out the possibility that some form of dualism will turn out to be true, and in fact I believe this will turn out to be the case. But classic Cartesian Dualism seems a rational non-starter for me.)

Therefore we need empiricism and observation to test which of our ideas is correct. Observation and empiricism are therefore important parts of science.

But the simple truth is that you can have science without these. Often you have no choice because the technology hasn’t developed yet to observe predictions made by scientific theories. The Large Hadron Collider is a good example of this; it might cost billions to make an observation. Worse yet, some observations may forever be cost prohibitive.

Furthermore, sometimes the smallest of observations cascade into the largest of ground shaking conclusions. As David Deutsch points out,

Thus observations of ever smaller physical effects have been forcing ever greater changes in our world-view. It may therefore seem that we are inferring ever grander conclusions from even scantier evidence. What justifies these inferences? (The Fabric of Reality, p. 57)

But this presents a difficult with defining science through observation.

Science is Not Always Falsifiable

Karl Popper is famous for having introduced the idea that science should be falsifiable. This is often interpreted as a theory not being ‘scientific’ unless it’s possible to falsify it. Again, I think this is a powerful idea that has a lot of truth to it. Is there any doubt that we should not take Freud’s non-falsifiable theories seriously any more now that we have better falsifiable psychological theories? A falsifiable theory is automatically better than a non-falsifiable one because the most productive theories make falsifiable predictions so that we can, to a degree, check them for verisimilitude. (i.e. closeness to reality.)

But I doubt this is what really defines science either. It would seem there are too many counter examples.

One of my favorite authors, Roger Penrose, points out that Popper-style falsification is simply not enough to exclude a theory from science.

…Karl Popper provided a reasonable-looking criterion for the scientific admissibility of a proposed theory, namely that it be observationally refutable. But I fear that this is too stringent a criterion… take the example of supersymmetry in modern particle physics. …it is a central ingredient of string theory. It status among theoreticians these days is so strong that it is almost considered to be part of today’s ‘standard’ particle-physics model. Yet, it has no (serious) experimental support… The theory predicts ‘superpartners’ for all the observed fundamental particles of Nature, but none of these has so far been observed. The reason [given]… is that a symmetry-breaking mechanism (of unknown nature) causes the superpartners to be so massive that the energies needed to create them are still beyond the scope of present-day accelerators. With increased energy capabilities, the superpartners might be found… But suppose that still no superpartners are actually found. Would this disprove the supersymmetry idea? Not at all. It could (and probably would) be argued that there had simply been too much optimism about the smallness of the degree of the symmetry breaking, and even higher energies would be needed to find the missing superpartner. [So] we see that it is not so easy to dislodge a popular theoretical idea through the traditional scientific method of crucial experimentation, even if that idea happened actually to be wrong. (The Road to Reality, p. 1020-1021)

Penrose goes on to use another example. One of our current theories predicts the existence of “monopoles.” Imagine a magnet that has only a north or a south pole and not both. If even one exists in the entire universe, this theory has been vindicated. But if we never find any it’s not really that shocking because what are the odds we’re going to find that one monopole somewhere out there in the entire universe? So here is yet another non-refutable theory. But few would argue it isn’t science.

Even Popper seems to disagree with this supposedly Popper-inspired idea, or at least he never says something isn’t science just because it can’t be falsified. Rather Popper only created a demarcation between what he calls ‘empirical theories’ and non-empirical ones. He goes on to say:

This criterion of demarcation between empirical and non-empirical theories I have also called the criterion of falsifiability or the criterion of refutability. It does not imply that irrefutable theories are false. Nor does it imply that they are meaningless. But it does imply that, as long as we cannot describe what a possible refutation of a certain theory would be like, that theory may be regarded as laying outside the field of empirical science. (The Myth of the Framework, p. 88)

Therefore a theory that is not refutable is only outside a category he calls ‘empirical science’ not necessarily science in general. [1] In fact, Popper points out that one of our most important theories – The Theory of Evolution – is based on a non-falsifiable core tenant; namely survival of the fittest:

There is a difficulty with Darwinism… it is far from clear what we should consider a possible refutation of the theory of natural selection. If… we accept the statistical definition of fitness which defines fitness by actual survival, then the theory of survival of the fittest becomes tautological, and irrefutable. (Myth of the Framework, p. 90) [2]

Are we prepared to dismiss the Theory of Evolution from the realm of science on the grounds that it’s central tenet is irrefutable? I would hope not.

So we see that ‘science’ is not primarily either observation nor falsification.


[1] Popper admits people misuse his epistemology based on faulty understandings of it. Using Pauli’s theory of the neutrino as an example, he says:

When this theory was first proposed by Pauli, it was clearly not testable. It was even said, at one time, that the neutrino is so defined that the theory cannot be tested. About thirty years later the theory was not only found to be testable, but to pass its tests with flying colours. This should be a warning to those who are inclined to say that nontestable theories are meaningless (a view which has often but mistakenly been attributed to me) or that they have no ‘cognitive significance.’ (Myth of the Framework, p. 88-89)

[2] It is my understanding that Popper at least partially retracted this quote later. I haven’t gotten that far in my reading of him yet. Truth be told, I do not think the theory of evolution could be said to be in any way non-falsifiable. But I do tend to agree that ‘survival of the fittest’ is circular reasoning. But this does not make the Theory of Evolution not a scientific theory, as Popper may have (at the time) been suggesting. It just means that we have to test other aspects of it based on that explanation.

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10 Responses to What is Science: Is Science about Observation or Falsification?

  1. Joseph Smidt on January 20, 2011 at 4:09 PM

    You use a good quote from Penrose to examine whether falsifiability is what defines science.

    But my response (and I think is the response by half of the rest of the physics community) is we have to be careful with scientific theories like supersymmetry because even if it is wrong there is no way to get it to go away and all of it’s supporters to stop and work on something else. Same can be said for string theory. Since it appears to be about impossible to falsify we might have scienists working on it forever even if it is false.

    For that reason, even though it may be philosophically wrong, (and using a phrase from the missionary manuels we used to use) science theores that are not falsifiable are still less-effective theories in my book. They are so fun to work on and have so much aesthetic appeal but even if they are wrong they are such that you can never really know.

    Falsifiable theories don’t seem to waste anyones time because if they are false you will soon find it out.

    And very interesting post and series thus far I must say. :)

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  2. Joseph Smidt on January 20, 2011 at 4:25 PM

    One more thing (and this is just playing a semantics game): some physicists have adopted the term “framework” for ideas like supersymmetry as SUSY can be used as a framework to generate specific SUSY models. The “framework” as a whole may not be falsifiable but each specific model is and so now people are happy that the unfalsifiable thing is being called a framework as opposed to a theory.

    But again this is still semantics and the problem still remains: how do you get physicists to stop generating SUSY models when there are always more to explore if SUSY as a whole is false.

    I guess one practical stop is at some point governments in principle will stop funding research that never produces anything. :)

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  3. Bruce on January 20, 2011 at 4:42 PM

    “But again this is still semantics and the problem still remains: how do you get physicists to stop generating SUSY models when there are always more to explore if SUSY as a whole is false.”

    This seems obvious to me: you generate a better theory that is falsifiable. If you can’t do that, then I believe there is justification to continue to work on it.

    I guess there is still the fear of the bandwagon effect. If it’s ‘popular’ to work on string theory, you’ll have people do it just out of the popularity.

    But this does not seem like a problem with science nor epistemology, per se. The fact is that if someone does come up with a theory that does all string theory can plus it’s falsifiable, string theory will disappear over night.

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  4. Joseph Smidt on January 20, 2011 at 5:21 PM

    “you generate a better theory that is falsifiable. If you can’t do that, ”

    Which is the current state of affairs. We haven’t been smart enough to come up with compelling alternatives so either the theory is true or we as a species are stuck and have been for a few decades now. :)

    So we need new data fast to either confirm SUSY or *hopefully* get us unstuck. But no matter what we see… as the joke goes one thing for sure is the data will agree with SUSY. :)

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  5. Bruce on January 20, 2011 at 5:58 PM


    I haven’t gotten to Kuhn yet, but Kuhn actually challenges the very idea that scientific theories can be falsified. Or maybe it would be more accurate to say that Kuhn believes they can only be ‘falsified’ compared to some other theory. (So you might as well call it ‘verification.’)

    I think Kuhn is basically right. However, I think it also misses the point of Popper’s falsificiation. It’s meant to help us generate more useful hypothesis.

    But once a hypothesis passes all existing tests, it becomes a theory. And at that point, you can really only dislodge it by coming up with a better theory. Observation *never* alone dislodges a prevailing theory. This, I think, Kuhn is correct about.

    So I’m not that worried about string theory. It deserves to be the prevailing theory right now because it answers the most questions (or we perceive it as doing so) and the way you dislodge it is exactly the same way we dislodged Netwon’s theories: you make up a better one.

    I have to confess, I have my doubts about string theory. That is to say, I believe it is probably all wrong. And from that point of view, I have to agree with what you are saying.

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  6. Jared* on January 20, 2011 at 7:13 PM

    re: Survival of the fittest is circular reasoning.

    Applied historically, and without other information, I can see how this might be so. A particular individual or species might survive because of chance rather than fitness. Gould and Lewontin famously criticized attributing everything to natural selection.

    However, here is an ordinary experiment: Take a mouse and inoculate it with equal portions of a regular strain of bacteria, and a mutant strain of the same bacteria. Wait for disease to develop. Kill the mouse and culture out the bacteria. Compare the proportion of normal vs mutant bacteria.

    If there is a lopsided result, it is clear that the survivors were fittest–because they survived. Only a crank or insane person would dismiss the obvious conclusion on the grounds of circular reasoning, which makes me suspect that it only superficially looks like circular reasoning.

    On a historical note, ‘survival of the fittest’ was not Darwin’s term. That came from Herbert Spencer.

    Another problem with falsification is that one can often modify components of a theory–and justifiably so. Bacteria cause cholera, but Max von Pettenkofer drank some in 1892 and did not get sick. Did this constitute falsification of Koch’s germ theory? Hardly. We may never know why Pettenkofer did not get sick, but we know that cholera is caused by a particular species of bacteria.

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  7. Joseph Smidt on January 20, 2011 at 8:33 PM


    Good, I’m excited you read your post on Kuhn then as it sounds like an interesting issue.

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  8. Stephen Marsh on January 20, 2011 at 9:34 PM

    If… we accept the statistical definition of fitness which defines fitness by actual survival, then the theory of survival of the fittest becomes tautological, and irrefutable.

    But realizing you’ve worked your way into a tautology is useful.

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