Are "theory" and "hypothesis" dead?

Do you understand the difference between a "hypothesis" and a "theory"? Physics professor Rhett Alain thinks you probably don't. But he says that's not your fault. The words just aren't terribly precise, at least in the public parlance, and they only serve to make discussions about science confusing. He has a modest proposal: Let's replace them both with something that makes sense to the general public.


  1. Alternatively, educate the public instead of replacing three importantly distinct terms with the generic and overly-vague word “model”. Apparently the purpose of the scientific method is to cater to imbeciles and the people who say “evolution is only a theory” (not mutually exclusive).

    1. But they’ll be so much happier to say “evolution is only a model” to make it sound unproven, because it actually could mean a mere hypothesis. Don’t you like making people happy?

      By being so general, model is a more confusing term than say “educated guess”. Which by the way means a guess informed by what you know; I don’t know why Allain thinks that doesn’t make sense.

      By the way, the post here has a typo in his name, it has 2 Ls.

    2. Or you could try teaching physicists some linguistics. Many words have different decodings according to context and education must also involve learning to hypothesize from previous occurrences which one is appropriate in any one given context in order to construct a theory and possibly a factual conclusion about what a word actually means and thereby communicate.

  2. A hypothesis is based on known values and is generally the premise of an experiment to elicit some empirical data, that may substantiate that hypothesis. 
    A theory is the extrapolation of an idea from know values using only simple reasoning. It may or may not be provable by empirical data.

    Or that is what is in my head right now, so I guess they are similar (and in some cases perhaps legitimately interchangeable). I would suggest the big difference is the ability to experiment to attempt to prove the idea. I don’t think you can have a hypothesis about something you can’t test about, while you can have some far fetched theory loosely based on some currently accepted ideas with no way to actually try and empirically prove it.

    Of course that could be mostly based on what I remember from grade 5 science fairs.

    1. They do overlap to some extent. I prefer to differentiate them mentally this way:

      A theory is what emerges after a hypothesis has been tested many times.

      1. Conversely, a hypothesis is a prediction that emerges from a theory.

        Given the theory of evolution, we can make a hypothesis that a population of bacteria placed in an ever-more-acidic environment will, after many generations, be able to survive in more acidic environments.

        If that prediction turns out to be correct, it lends more weight to the original theory.

      2.  I agree with SamSam .. You have a theory, produce a hypothesis based on the theory and test that hypothesis.

  3.  Remember when Kuhn freaked out about how “paradigm” entered the common parlance?  Actually, now that I think about it, the fact that the same thing happened to “meme” is pretty funny.  Evolve, little meme!

  4. I understand that it’s frustrataing, having to deal with the shortcomings of a general audience that is unaware of the precise meanings of terms used in any given discipline (or even in what I used to think of as educated discourse), but as has already been pointed out, “model” is actually less precise, because more general. For example, imagine a discussion with someone who is not hostile but only uninformed:

    “What do you mean, ‘model’?”

    “It’s a whole set of ideas about how some physical process works.”

    “How do you get a model?”

    “Um, you start with some data, then you form a hypothesis that might explain it. . . .”

    And we’re right back to the problem of explaining exactly what kind of constructs lead to a scientific theory or law. I find it more useful in such discussions (note that I’m not a scientist but a writer, ex-teacher, and general word-guy) to be able to offer one or more equivalent terms, often borrowed from corners of my long-ago courses in logic, epistemology, and such–“proposition” for “hypothesis,” for example, is useful because it is a fairly familiar term, and in logic (if I recall my old coursework correctly) it is a sentence that can be true or false–and if it’s a testable true-or-false statement, there we are in the science room again.

    Actually, I’m quite fond of “model” as alternate term for theory and of emphasizing how a scientific model is about both explaining and predicting, but above all “accounting for” how-things-work and what-things-are. And, oddly enough, I have used a lot of the same language in talking about non-science matters, including literary analysis. Epistemology, logic, and rhetoric are at the bottom of all systematic, rigorous, functional discussion. (There’s metaphysics in there, too, but I’ve always thought that it’s a destination rather than an origin point.)

    1. So how is your mental model of this area of linguistics holding up? ;)

      Actually I’m all in favour of treating a lot of dogma as models. Maybe it would encourage a more evidence-based view of their accuracy and applicability. Or to paraphrase Oliver Cromwell, “I beseech you, in the bowels of Christ, think it possible that your model may be of limited use in predicting future states of objective reality.”

  5. In order to clarify why such terms as theory and hypothesis are used in science instead of the word proof when dealing with ideas about how nature works one must realize that our knowledge in this area always remains incomplete. It can never be logically appropriate to claim you have proven that an idea about how things work is absolutely true when a fact disproving it can suddenly pop up for all we know. So any attempt to understand nature must keep this in mind.
    People have always wanted to understand the world, but before the creation of the scientific method the authority of some revered person such as Aristotle who had eloquently speculated on the nature of things was taken at face value. So for thousands of years very little progress was made.
    The scientific approach is to first speculate based of some preliminary analysis. This is generally called a hypothesis. For any such hypothesis to be accepted as scientifically sound must imply that there are facts about the world that must be true if the hypothesis is true. The step that distinguishes science from previous efforts comes in rigorously testing the hypothesis against these facts. As the hypothesis successfully meets challenges it becomes considered more and more sound, and at some point it effectively becomes accepted as true, but not absolutely so, if there is no competing hypothesis which is as successful, and is called then a theory.
    This is a broad simplification of course, but is the basic way science creates usable knowledge of the world, and so far is the only way which allows the human mind to penetrate beyond the common sense, rule of thumb perspective.  

  6. The problem is that “model” can have a precise technical meaning as some specific instance that “satisfies” some data or “theory”, and that data or theories don’t necessarily have a unique model.

    For a crude example one could say a theory of arithmetic can be modeled with the integers or the real numbers and these two models are hardly the same.

  7. We could alternatively make up some new jargon.

    I propose that instead of “theory”, I say we call it a “monoconceptualisation”, and instead of “hypothesis”, we say “pre”. Which is short for some other jargon.

    Once these terms become assimilated into English and mean something completely different, then we can move on to yet more terms.

    Or we can just deal with the fact that sometimes, words have two meanings; the jargon one and the specific one. Chronic, shock, vagina, theory, hypothesis, moot, and so on.

  8. I think physics envy is part of the problem. Not everything can be reduced to simple pass-or-fail, maybe-or-no experiments. Some things require more observations. So a *testable* hypothesis or set of hypotheses in an experiment, or in another hypothesis-testing approach, is different from a *not-yet-testable* hypothesis in a set of possibilities.

    Maybe it makes more sense to speak of proposed models, working models, useful models, somewhat tested models, etc.

  9. >  Let’s replace them both with something that makes sense to the general public.

    Or, let’s invest more in science education and combat the attempts of organized, denialist religion to invade the public schools.

  10. Because there’s no chance the new words will be misused in the precise manner of the old words.

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