Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The perfect theory falsifiable?

  1. Jun 13, 2006 #1
    Hi. Maybe I don't understand Popper correctly. He says that a proper scientific theory should be falsifiable. Now, let's suppose that there is a perfect scientific "ultimate" theory explaining all physical phenomena accurately. Is this theory falsifiable? Does it then pass the test for a scientific theory?

    Is my question flawed perhaps?
  2. jcsd
  3. Jun 13, 2006 #2
    It depends on how the theory is stated. Perhaps you can answer your own question. What does it mean for a theory to be "falsifiable"?
  4. Jun 14, 2006 #3
    A scientific law or theory is "falsifiable" if one can show that an exception to the law or theory is logically possible. Hence there cannot be any "perfect" or "final" scientific theory, since per definition it would not be falsifiable - that is if we accept Popper's idea of a proper scientific theory.

    Yes, wave, I answered it myself, but are there not many scientists who are looking for a final theory?
  5. Jun 14, 2006 #4
    Are you sure? Consider the hypothesis "all ravens are black" and suppose it is "perfect" (i.e. no counterexamples exist). You won't find any instances of albino ravens, but such a counterexample is not necessarily logically impossible, right?
  6. Jun 14, 2006 #5


    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    Falsifiable does not mean successfully falsified. And it has nothing to do with the explanatory range of the subject. A "perfect" theory will make predictions in many areas which can be checked, otherwise it wouldn't be perfect (as superstring theory, which does not do this, is not granted the dignity of perfection). And every time such a prediction is checked, there arises the possibility that the beautiful perfect theory could be falsified.
  7. Jun 15, 2006 #6


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Note, for example, that any perfect theory must agree with every single correct prediction we can make concerning our everyday world (within experimental error margins). If it doesn't, the theory is wrong.
  8. Jun 19, 2006 #7
    wave, i am not using the term "perfect theory" lightly. If a theory "all ravens are black" is truly blessed with the term "perfect" (i.e. no counterexample exists or will ever exist), no exception is possible, not even logically. Agree? I argue that we will never know when we hit the perfect theory - we will allways have to regard it as tentative. When anyone claims to discover the perfect or final theory, science is inherently abandoned.
    Last edited: Jun 19, 2006
  9. Jun 19, 2006 #8
    No. Like I said, an albino raven is a counterexample. Why is it logically impossible given the way the hypothesis is stated?

    I don't see why a "perfect" theory, as you have defined above, cannot be held tentatively.
  10. Jun 19, 2006 #9
    Question. Can we say then that theory of quantum mechanics is a "perfect" theory, since it would appear that none of the predictions it makes have been falsified by any experiment ?
  11. Jun 20, 2006 #10


    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Not in the sense of toogood's requirement, I believe:
    As I understand it, for toogood a PERFECT theory should be NECESSARILY true, that is, it must have been proven that any possible alternative theory is self-contradictory.

    This, at least, is how I read toogood's posts.
  12. Jun 20, 2006 #11
    Terminology is unfalsifiable, except if your a philosopher or ethicist :tongue:

    All Zonkerithenes are Weeblethylenes. You can't disprove that because I came up with these words, it's my language so use it. =P
  13. Jun 20, 2006 #12
    First principles cannot arise through reason, and if a principle does arrive by reason, it is not a first principle. A theory made entirely of first principles is unfalsifiable.

    History is unfalsifiable to a great extent, insofar as whatever is goes on in the present cannot possibly give any reason that the history is false without first establishing unfalsifiable first principles concerning history.
  14. Jun 22, 2006 #13
    Arildno, you said it better than I could. Wave, I suspect we only disagree on terminology. From my side I would appreciate if we could agree that the attribute "perfect" for a theory implies that no counterexample to the theory is possible in whichever sense. If a contradicition is possible logically or otherwise, the theory is imperfect.

    Hence my contention is really a tautology, but an interesting one: We will never know whether any given theory is perfect in the strict sense of the word. Even if we discover the perfect theory, we will never know for certain that we discovered it. Even if the theory survives a thousand years, we can never view it as anything else than tentative. I repeat: when anyone claims to discover the perfect or final theory, science is inherently abandoned.
  15. Jun 22, 2006 #14
    OK. So which types of unfalsifiable theories would qualify as "perfect"? If not all, then please state the complete criteria.
  16. Jun 23, 2006 #15
    Difficult question. According to my idea of a "perfect theory", "perfect" certainly implies "unfalsifiable". About the converse I am not certain. I think you are right that my definition of a perfect theory implies the converse - hence a theory is Unfalsifiable if and only if it is Perfect according to my current definition. This seems unsatisfactory and I agree that a proper definition of a perfect theory should be more specific. The theory "everything, past, present and future is a result of the all-powerful will of X" is also a "perfect" theory according to my current definition. This theory does have a powerful ability to explain phenomena, but a complete inability to make specific predictions.

    Hence, perhaps the definition of a perfect theory should at least include an ability to predict specific outcomes perfectly and not only explain things perfectly.
    Last edited: Jun 23, 2006
  17. Jun 23, 2006 #16
    The perfect theory is like the perfect murder, a contradiction of terms.
  18. Jun 28, 2006 #17
    Well, a perfect murder is only an ethical contradiction, not a logical, isn’t it?.

    Anyway as said, a theory is the promotion of a hypothesis, when its forthcoming predictions proved to be correct. A theory would remain the best possible approximation of the truth until it is falsified by a new “ugly fact”*; that’s all standard Popper

    Hence, hypothetically, a perfect theory is only possible when it has survived all new facts and there will be no more opposing facts to be discovered, because we know everything in that area.

    But one could also argue that a perfect theory is a universal physical law.


    *”The Great Tragedy of Science, the slaying of a beautiful theory by an ugly fact.” Thomas Huxley
  19. Jun 30, 2006 #18
    Well, no, a "perfect theory" is a contradiction of logic, because science is based on a philosophy of "uncertain knowledge"--thus the situation you talk about above (e.g., the time when humans will know all facts in this area of study or that) is "logically" impossible. One example, the Heisenberg Uncertainty Principle (HUP) of physics tells us that this fact (e.g., certain knowledge of simultaneous position and momentum of a thing) is not just difficult, but logically impossible. Thus humans will never "discover" the "perfect theory" (which is same as saying the perfect explanation) of the simultaneous existence of position and momentum.
    I do not hold a philosophic view of dualism between facts and values, e.g., values do not constitute a separate identity distinct from existence, thus in my mind a perfect murder is not only a ethical contradiction but also a logical contradiction.
  20. Jun 30, 2006 #19


    User Avatar
    Staff Emeritus
    Gold Member
    Dearly Missed

    I see what you mean, but I don't think this is right. Logic per se is radically a priori, as Kant would say, while the empirical constraint of uncertain knowledge is just as radically a postiori. Reasoning from one to the other would seem to be a category error. But maybe I misunderstand?
  21. Jul 6, 2006 #20


    User Avatar
    Science Advisor

    No, a "perfect" theory, at least in the sense of the "theory of everything", is not a contradiction. The difficulty is that the original poster seems to assume that a "perfect theory" must be logically perfect as well- there is no logical possibility for it to be wrong. That is certainly not required of a physics theory. The requirement for a theory in physics to be "perfect" is that it pass every conceivable test.

    Of course, since there are an infinite number of conceivable tests, while it is possible to have a "perfect theory", it would be impossible to know that it was perfect!
  22. Jul 7, 2006 #21
    Not trying to beat a dead horse, but I do not agree. In science, a "theory of everything" would represent "uncertain explanation of everything" since science = uncertain knowledge and theory = attempt to offer explanation of such knowledge. Because uncertain explanation must logically lack perfection, the "perfect theory" can never exist in science.

    How so ? Consider the concept of "information" which can be reasoned as nothing more than a priori constraint on a posteriori probability. Via the dialectic, what is "before" the fact and what comes "after" the fact provides the holistic reality of the fact, so it seems to me.
  23. Jul 8, 2006 #22


    User Avatar
    Staff Emeritus
    Gold Member

    HallsofIvy is using the term "perfect" a little more liberally than you are, just to mean that a theory of everything would be perfect in the sense that it is universally applicable to explain any given physical interaction.

    However, you are of course right if we take "perfect" to mean something along the lines of "infallible," which no scientific theory can ever be. In that case, we'd be saying the perfect theory is both infallible (because it's perfect) and fallible (because it's a theory), the very definition of a contradiction.

    This is just a terminology dispute, though. The opening post did not exactly give a precise definition of what it meant by "perfect," but the impression I got was a complete theory that explained the operations of all physical forces, which admittedly, isn't really perfect in the strictest sense.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook