Theories, laws, facts

Could we just agree to tell the truth about this from now on? The New York Times has an interesting story by Cornelia Dean on the training that museums have started to give their docents and employees on how to deal with creationists. A sad commentary on our current state of affairs that such training is becoming necessary, but probably nobody reading this blog is surprised.

But as a supplement to the article, the Times reprints a FAQ from a pamphlet handed out by the Museum of the Earth in Ithaca, N.Y. It includes the following question:

Is evolution ‘just a theory’? A “theory” in science is a structure of related ideas that explains one or more natural phenomena and is supported by observations from the natural world; it is not something less than a “fact.” Theories actually occupy the highest, not the lowest, rank among scientific ideas. … Evolution is a “theory” in the same way that the idea that matter is made of atoms is a theory.

This is right in spirit, but the truth is not so very scary or technical that we can’t just fess up to it. The truth is that the hierarchy of “hypotheses” and “theories” and “laws” and “facts” that many people are taught in elementary school (or wherever) has absolutely no relationship to how real scientists use those words. Which is, that they are completely inconsistent and sloppy with their use. There is no procedure by which an ambitious young Hypothesis accumulates some promising support, and is brought up before the Most Supreme Council of Learned Scientists to be promoted to a Theory.

The reality of the situation is that it’s a mess. I can invent a half-baked idea tonight and call it a “model” or a “theory” and nobody cares, or would even notice. The Standard Model of Particle Physics is much closer to objective truth than Newton’s Law of Universal Gravitation, and the General Theory of Relativity is somewhere in between.

And “facts”? Eavesdrop on some scientists at work. You will go years without hearing any of them talk about “facts.” They’ll talk about data, and measurements, and observations, and experiments — those are things with identifiable meanings that we can work with. But call something a “fact” and you’re making some absolute metaphysical claim that isn’t the kind of thing scientists like to do. Likewise “proof.” Mathematicians and logicians, who deal with abstract symbols independent of any connection to nature, prove things. Scientists don’t. They figure out that certain beliefs should be held with greater and greater confidence, but proving something is simply outside the domain of science.

Which does bring us to the one almost-subtle point in this generally easy-to-understand business. Science never gets anything 100% right; it is always working on a better understanding, improving on the best current theory (or model, or whatever). But it does get some things right enough. The Big Bang, the round earth, Newton’s Laws, the Standard Model, natural selection — none of these is “proven” correct, but they are all correct, within certain domains of validity. There comes a point when, even though you can never (even in principle) prove an idea to be a fact, it becomes well-enough established that maintaining a skeptical attitude is a sign of crackpottery, not wisdom.

So let’s just quit the charade and let the unwashed masses in on the truth as far as “theory” is concerned. It’s a shorthand term for a model of some part of nature — but the label implies absolutely nothing about how true that model is. (The phlogiston theory didn’t stop being a theory once we knew it wasn’t true.) What matters isn’t whether we label something a “theory” or a “law” or a “fact,” it’s whether we label it “right” or “wrong.” As in, Darwin was “right,” the creationists are “wrong.”

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45 Responses to Theories, laws, facts

  1. The Anti-Lubos says:

    At the same time, I think you have to concede that a theory does have to make falsifiable predictions; as you say, they don’t have to be right, but they do have to be there. It is possible for an idea to be sufficiently empty of content that it fails even to earn the label “theory” or “model.”

  2. The gap between science and the popular understanding is probably not much diminished by the use of phrases like “unwashed masses” or “kindergarden version.”

  3. Peter Erwin says:

    The problem is that the word “theory” does have common uses outside of science, which encourage non-scientists to think of scientific theories-with-a-capital-T (evolution by natural selection, Big Bang, General Relativity, etc.) as embracing the kind of half-assed speculation people engage in every day. (As in: “Well, my theory about what’s really going on in this season of 24 is…”)

    And I’d disagree with you slightly about the actual situation in science (at least from my perspective ;-). Yes, you can come up with a quick, half-baked idea and call it a “theory”, but I suspect other scientists will think you’re being a bit pompous; that’s we why also have the terms “hypothesis” and “model” (and “toy model” and “cartoon”…). The word “theory”, in a scientific context, does imply some intellectual weight: some structure, some consistency and coherence, some elaboration, some serious work put into it.

  4. Mark says:

    Anti-Lubos. I think what Sean is saying is that we don’t care in general – the word “theory” just gets thrown around with abandon. Your requirement is certainly one of the things that must be satisfied to qualify as science though.

    I do think the museum training is fine though. It is in the right spirit, and given time constraints should work OK.

  5. Wolfgang says:

    Sean,

    I would think there is a much better answer to this “just a theory” argument:

    If evolution is “just a theory” then it is also “just a theory” that Jesus Christ
    lived and walked on the earth approximatley 2000 years ago.
    Actually, the latter is “just a theory” as far as I know 😎

  6. Adam says:

    Personally, I think it’s pretty important that scientists remember that it’s not about ‘right and wrong’ but about whether or not it’s been disproved (‘wrong’) with the absence of disproof not meaning ‘right’. That scientists are sloppy in their terminology is irrelevant to how the creationist/ID types should be replied to, I’d say; sure, it perhaps doesn’t flatter the average scientist to point that out (but again, is it relevant? How we speak in day to day usage and what we understand underlies our work are different things), but the attack levelled by creationists and, particularly, the ID people, is at the foundations of science and it back upon those that we should fall to prepare our refutations.

    I don’t think that evolution is ‘true’ (or even particularly scientific*, to be honest, for all that it’s more scientific than any other attempted explanation; furthermore, I think that this deficiency is unavoidable and certainly shouldn’t be used as a rod with which to attack Darwinism/evolution. Indeed, I think that the use of ‘scientificness as sole criterion of worth’ is as much a crock as it was when the logical positivists attempted to use it to demarc meaning from non-meaning) but it’s a ‘good theory’, in fact, the ‘best theory’. I think that if we claim evolution to be ‘true’ or ‘right’ (at least, without qualifying that by ‘right’ we mean something like ‘best theory yet to be disproved’) then we’re not only making a mistake of logic but we’re giving ammunition to the loons.

    Of course, the criterion of worth for deciding what is the best theory not yet disproved is hardly uncontentious in itself. But I do think that, if nothing else, we should make clear that it’s not a symmetrical situation, that while we can perhaps find theories to be ‘wrong’, we can’t prove them right. To my mind, saying ‘right enough’ is just an invitation to a handwaving competition and, frankly, we’re outnumbered in terms of hands; better to stick to the logical foundations of the scientific endeavour, I say. Even if the handwaving ‘right enough’ approach could win the argument, it’d be winning in the wrong way, I think, and I don’t believe that winning on this battleground is so important that it doesn’t matter how we do it.

    *All I mean by this is that it’s hard to make predictions that can be falsified. It’s not a criticism, because the difficulty is in the subject matter rather than the approach, a statement that can’t be applied to ID ‘theories’ (which perversely adds additional difficulty into making disproveable claims).

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  8. iso42 says:

    > I think that if we claim evolution to be ‘true’ or ‘right’ (at least, without qualifying
    > that by ‘right’ we mean something like ‘best theory yet to be disproved’) then
    > we’re not only making a mistake of logic but we’re giving ammunition to the
    > loons.

    Adam,

    please do me a favor: The next time you state that the sun will rise tomorrow
    (or is very likely to rise tomorrow), you should qualify that this is based on
    “the best theory yet to be disproved”. Then you would not make a mistake of
    logic and not give ammunition to the loons.

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  10. Adam says:

    Iso42

    You are perhaps misreading what I said. I am talking primarily about the debate with the ID/creationists, not the everyday usage of language when the people you are communicating with understand what’s implied (indeed, I asked if the everyday use was even relevant to this issue). So, when I say to myself that the sun will come up tomorrow, I am aware of the inductive implications of the statement on the face of it and, thus, don’t need to qualify it.

    When I am teaching physics, however, I make the point (early on) that we can’t prove anything and from then on I would use normal language, having established what really underlies my statements (unless I believe that the class is already aware of the nature of science, in which case there is no need to). That’s a perfectly acceptable verbal shorthand, I think. When debating with ID/Creationist types who base their attacks on a misunderstanding of science, I believe that it behooves us to be precise, as it is in this way that we will best confound their arguments. The shorthand I mentioned previously is only for use amongst groups where we all know what it abbreviates; when we are talking to a group who patently don’t, as evidenced by the thrust of their attack, the shorthand should be eschewed in favour of precision.

  11. iso42 says:

    Adam,

    you make a good point:

    > I am talking primarily about the debate with the ID/creationists, not the
    > everyday usage of language when the people you are communicating with
    > understand what’s implied

    ID and Creationism is not the everyday usage of language …

    Very good point!

  12. Anonymous says:

    Adam,

    Evolution is plenty falsifiable – see TalkOrigins.org for an exhaustive list of evidence and potential falsifications.

  13. Darwin says:

    String theory is an interesting example of a model, not a theory. The 10/11-D M-theory is really a mathematical model that explains supersymmetry and is also consistent with supergravity with 6/7 dimensions rolled up in to the Calabi-Tau manifold.

    Is this reality? Witten seemed to think so when he wrote: ‘String theory has the remarkable property of predicting gravity’. (Edward Witten, Physics Today, April 1996.)

    Since Witten had proved the equivalence of 10-D string theory with 11-D supergravity in 1995, he was entitled to write that from his perspective. But I don’t think it particularly helpful to talk like that, it sounds a very similar to Edward Teller’s hyping description of the X-ray laser (Teller said something like: ‘it has the remarkable property of being the size of an executive suitcase and able to shoot down the entire Soviet missile force, if in its field of view’.)

    No field theories are currently causal: beyond the vague idea that gauge boson exchange gives rise to force, there is no interest in treating fundamental forces as arising from a physical cause like radiation pressure.

    In 1919, Theodor Kaluza wrote a paper that put 5 dimensions instead of 4 into the metric of general relativity, obtaining electromagnetism. In 1926 Oskar Klein suggested the extra dimension was unseen normally because it was rolled up into a small (sub-atomic sized) circle, forming the fundamental particles of matter. However more dimensions were found to be required to explain supersymmetry in the standard model and the weak force.

    It is clear that gravity is the major problem in physics. In Dr Randall’s book ‘Warped Passages’, on page 6 we read: ‘A tiny magnet can lift a paper clip, even though all the mass of the Earth is pulling it in the opposite direction. Why is gravity so defenceless against the small tug of a tiny magnet? In standard three-dimensional particle physics, the weakness of gravity is a huge problem [the ‘hierarchy problem’, the differences in the strengths of the fundamental forces]. But extra dimensions might provide an answer.’

    However, Dr Randall’s suggestion that a dimension is stretched out does not offer a quantitative prediction of the coupling constant for gravity, a factor of only 10^-40 or so of the electromagnetic force strength.

    It is obvious from the sort of input you can put into string theory that you are not going to get the coupling constant for gravity, 10^-40.

    To answer this you need LeSage, who suggested gravity is a pushing effect in 1748 and used it to predict the nuclear atom (because the force would have to penetrate atoms to act on every particle of matter, not just on the outer surface area of a planet): George Louis LeSage, Lucrece Newtonien, Nouveaux Memoires De L’Academie Royal de Sciences et Belle Letters, 1782, pp. 404-31. It is online at http://www3.bbaw.de/bibliothek/digital/struktur/03-nouv/1782/jpg-0600/00000495.htm

    In CERN preprint EXT-2004-007 and in two Electronics World articles I showed that Feynman’s ideas on presenting general relativity as a compressing force of the spacetime fabric were equivalent to the Lorentz contraction: the spacetime fabric pressure when moving shortens objects in the direction of motion, and the contraction term in general relativity supplies the same effect for gravity.

    ‘… the source of the gravitational field can be taken to be a perfect fluid…. A fluid is a continuum that ‘flows’… A perfect fluid is defined as one in which all antislipping forces are zero, and the only force between neighboring fluid elements is pressure.’ — Bernard Schutz, ‘General Relativity’, Cambridge University Press, 1986, pp. 89-90.

    ‘It was proposed that a mechanism of gravity should be developed to rigorously test all of the consequences of the physical fluid model for the fabric of space… The success of this model for gravity has implications for the unification of fundamental forces via quantum theory.’ — Nigel Cook, ‘Solution to a Problem with General Relativity’, CERN Document Server paper preprint EXT-2004-007.

    The paper is at http://nigelcook0.tripod.com/ and shows that for the correct mechanism of gravity due to LeSage, the critical density is exactly .5e^3 (or about 10 times) higher than the true density. Hence most of the dark matter is eliminated, enabling an energy balance to become feasible. This predicts the strength of gravity, G.

    Notice that Einstein and Dirac recognised the importance of spacetime fabric (they called it ether, although it is radiation and is not the same as the 19th century models):

    ‘According to the general theory of relativity space without ether is unthinkable.’ — Albert Einstein, Leyden university lecture ‘Ether and Relativity’, 1920. (A. Einstein, Sidelights on Relativity, Dover, 1952, p. 23.)

    ‘… with the new theory of electrodynamics [vacuum filled with virtual particles] we are rather forced to have an aether.’ — P.A.M. Dirac, ‘Is There an Aether?,’ Nature, v168, 1951, p906. (If you have a kid playing with magnets, how do you explain the pull and push forces felt through space? As ‘magic’?)

    I think this is consistent with string theory, not an ‘alternative’ as such, because string theory is a successful explanation of the standard model, not force strengths.

  14. Adam says:

    Anonymous:

    I’m not saying that it’s not falsifiable, I’m saying that in principle statements about past events of relative complexity over extremely long periods of time are more difficult to subject to exhaustive falsifiable investigation than are, for example, statements about the conservation of momentum. That evolution can occur is what we can show, of course.

    As I say, it’s not a criticism. As an aside, I don’t think that we can claim that any other scientific theory is truth, either. I don’t think that ‘scientificness’ (in the sense of ‘falsifiability’) is a measure of worth for anything other than how scientific something is; that I don’t think that evolution is as scientific as other theories isn’t a measure of the theory’s worth. As a further aside, I also don’t think that there is any point trying to disprove ID or Creationism in total (given that you can always Deus ex Machina your way out of any scientific attacks on them), or show that they are worthless, or try to show that God doesn’t exist or that, if he does, he doesn’t do anything; the aim is to show that ID and/or Creationism don’t belong in a science classroom. They aren’t ‘competing theories’ in the scientific sense, even if they are alternative explanations for the same observations.

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  16. Watcher says:

    Sean you may have implied this but didn’t make it explicit or emphatic enough for me: in order for the enterprise you describe to be successful, scientific theories have to make predictions which allow them to be tested. Here’s what you identify as a key passage:

    Which does bring us to the one almost-subtle point in this generally easy-to-understand business. Science never gets anything 100% right; it is always working on a better understanding, improving on the best current theory (or model, or whatever). But it does get some things right enough. The Big Bang, the round earth, Newton’s Laws, the Standard Model, natural selection — none of these is “proven” correct, but they are all correct, within certain domains of validity. There comes a point when, even though you can never (even in principle) prove an idea to be a fact, it becomes well-enough established that maintaining a skeptical attitude is a sign of crackpottery, not wisdom.

    To expand, or paraphrase, there has to be some mechanism whereby reasonable people can agree on what is well-established and what isn’t. To function successfully, different factions in the scientific community have to be able to arrive at consensus on what is inbounds wisdom and what is out-of-bounds crackpot. This agreement is ultimately based on the goldstandard of experimental observation. So there is a kind of moral obligation theorists have to derive predictions from their models which make them vulnerable to empirical refutation. Basically this is for the good of the community, for the continuance of this tradition you allude to: of being able to reconcile opposing views by recourse to observation.

    A key part of the quote is “Science never gets anything 100 percent right,” and it could be said that proving theories right is not what it’s about—its about proving them wrong (or restricting the range of validity.)

  17. Arun says:

    Adam wrote:

    I’m not saying that it’s not falsifiable, I’m saying that in principle statements about past events of relative complexity over extremely long periods of time are more difficult to subject to exhaustive falsifiable investigation than are, for example, statements about the conservation of momentum. That evolution can occur is what we can show, of course.

    What are the current experimental limits on the non-conservation of momentum at redshift z=10?

  18. Plato says:

    So does it come down too, “is it just guessing, or does it have a predictable value”? Am I moving away from the valuation sought by scientists?

    Tried looking for statement I asked of Lubos in reference to my nine year old grandson. My grandson concluded after I explained what a model was, that it was based on previous work done and extensions of it, that he figured it was still guessing.

    I thought he might be right? It inspired this.

    So thanks Sean for the wise counsell. Maybe Lubos can add his comment in relation to yours, that further dialogue can further establish, a true and sanctioned method by all scientists to this “valuation” being assigned.

    Lee and Lubos should continue their talk without interruption, to make it clear what demands are being placed on further idealizations about this perspective that is driving scientists forward?

    It’s ramifications in cosmological arena. Would this all be considered responsible?

  19. Plato says:

    should read:

    Lee and Lubos should continue their talk without interruption…

    Lee and Lubos

  20. Adam says:

    Arun:

    Search me. But if you’re trying to say that conservation of momentum is comparably falsifiable to evolution, you’d have to be a bit more precise for daft old me to understand. Is the hot debate (if there is any) over conservation of momentum centered around whether momentum was conserved billions of years go? If it is, such a debate would also be difficult to falsify (although at least we have, in principle, direct evidence of events from billions of years ago; indeed, it’s as if it’s happening in the now, to a large extent, observationally, for all that it’s faint). I was talking about whether momentum is conserved today as the (somewhat offhand) exemplar. The question of ‘how did current life come to be as it is’ is a more difficult topic for falsifiable investigation (one could indeed make the same claims about cosmology, although in some sense cosmologists do have direct contemporary evidence for some times, even if contaminated).

    In any case, I would reiterate that I put no merit in the idea of ‘scientificness’ or falsifiability as some sort of a criterion of objective worth in any case. Just so we’re clear; I’m not accusing you of taking my comments that I don’t personally think that evolution is as ‘scientific’ as some other theories as some sort of condemnation of it, but I’d like to reiterate anyhow that such is not the case. ‘Scientific’ isn’t the same as ‘good’, at least not so far as I’m concerned. I also don’t think that it’s a problem in the ID/evolution debate, because that debate is about whether or not ID should be taught in science as a competing scientific theory to that of evolution and clearly it isn’t. ID is enormously ‘unscientific’ and is, of course, enormously less ‘scientific’ than the theory of evolution and, thus, shouldn’t be taught in science lessons. Such scientific debate that takes place amongst the community, that is accessible, would indeed be interesting to include (Dawkins and the other chap, I think, mentioned that in a piece that was quoted in this very blog; the one where they unfortunately said that the Scopes Monkey trial took place in Kansas), but ID isn’t it.

  21. joke says:

    Adam,
    This is bizarre. Are you equating “scientificness” with amenability to precision measurement? So somehow particle physics is more scientific than geology, cosmology, evolutionary biology? That is hard for me to understand. I don’t think that’s a very constructive definition of science.
    Joke

  22. Adam says:

    joke:

    No, I’m equating it with falsifiability. It’s not an idea I invented, incidentally, and it isn’t uncontentious.

    I would say that some areas of physics weren’t particularly scientific, for that matter (arguments about interpretations of quantum mechanics, for example).

  23. Arun says:

    Thinking about it over lunch, I’d say evolution is as much of a fact as the conservation of momentum. That is, given some basic things, such as organisms that reproduce, but with variation, and this, in a non-random way, results in variation in reproductive success, I’d be hard-pressed to prove that evolution does not occur.

    The question that is open is are the mechanisms of evolution described so far sufficient to explain all that we see, or are there additional ones? E.g, Lynn Margulis’s theory of symbiogenesis is a significant addition to the original mechanisms of evolution described by Darwin.

  24. iso42 says:

    Adam,

    > I was talking about whether momentum is conserved today

    as they say: tomorrow, today will be yesterday.
    All we know is based on memory and documents from the past.
    There is no qualitative difference between a lab-logbook, a fossil
    or The Holy Bible. They are all documents from the past and we can
    never be certain that they are not misleading.

  25. Adam says:

    iso42:

    The nature of the risk of them being incorrect is different, though, I think, as is the likelihood of information being lost, to that contained in the evolutionary record. I’m not, incidentally, subscribing to the idea that the future, the present and the past are the same thing, although I certainly have the working hypothesis that they have the same rules.

    On the subject of falsificationism, though, here is an interesting page of criticisms (many of which don’t bother me, but do motivate those that aren’t falsificationists): http://www.galilean-library.org/falsificationism.html (linked from the wikipedia page on falsificationism, I think).

    My main concern, actually, is not what science is or isn’t* so much as the idea that something that isn’t science (or, at least, not as scientific as something else) is less meaningful. I just wouldn’t teach it in science class (whether or not I believed it; evolution, however, is certainly the horse I’d back in the race to explain current day diversity of species).

    *I mean, I’m very interested in this question, but I’m also concerned that the criterion for what is and what isn’t science doesn’t become a line, implicitly, between what is and what isn’t good, or does or doesn’t have worth, etc.