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"A witty saying proves nothing" Voltaire. "All your bias are belong to us" Ara Pacis. Last edited by Disinfo Agent; 23-July-2008 at 06:57 PM.. Reason: quote added -- nothing like looking at the source |
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. |
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Don't be naive.
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"A witty saying proves nothing" Voltaire. "All your bias are belong to us" Ara Pacis. |
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‘To those who regard “crime fiction” as some sacred icon which must follow a rigid formula, I will always be the man who writes 18-syllable haiku.’ Andrew Vachss, Autobiographical essay Trying to make sense of computers, The Error Log.
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![]() KenG, I certainly don't have a problem with what you said earlier: Quote:
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But now to the topic of this thread. I actually like KenG's reference to the "usefulness" of a theory in the above quote much better than "falsification". For example, introductory chemistry classes instruct students on the combined gas law and the ideal gas law even though these gas laws are "falsified" due to the fact that real gases experience particle attractions that cause them to deviate from the ideal gas law. A better equation is the van der Waals equation which is a modification of the ideal gas law. However, the ideal gas law is still useful because it is a good approximation (at least for pedagogical purposes). Newton's laws fall under this category - they still have practical application because we can make accurate enough predictions with them for many purposes. CDM also is still useful on the scale of galaxy clusters and superclusters and where cosmology is concerned. CDM simulations seem to reproduce the large scale structure. CDM helps to fulfull the needs of a flat inflationary universe. CDM allows cosmologists to make predictions that can then be observationally tested. All this works on galaxy cluster scales - and there are successes on that scale that justify the usefulness of CDM. But my point in the other thread is that on galaxy scales - CDM has met with one failure after another when the expectations are compared with observations. The expectations for CDM particles are not verified on galaxy scales. The other thread is where we're discussing that evidence specifically. However, given those failures - and speaking to the topic of this thread - CDM is not very useful for understanding the observations of the dynamics of individual galaxies. You can make predictions with CDM for galaxy dynamics, but those predictions are repeatedly contradicted by observational results. And that is why I used the word "falsification". What use is a hypothesis which has predictions that are repeatedly shown to be in conflict with observations? Now if someone thinks it is premature to say CDM cannot be made to fit with those observations being discussed on the other thread, that is fine. However, the motivation for continuing to use CDM on galaxy scales is not because of any galaxy scale successes, but because of the compatibility of CDM with galaxy cluster observations and cosmological theory. My purpose in the other thread was to point this out. CDM is one of the key components of cosmological theory. And like it or not - galaxy scales is part of the foundation upon which the continued usefulness of CDM rests.
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"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known." ~Timothy Ferris (The Red Limit) 1982 |
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Hmmm ... on what basis?
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"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known." ~Timothy Ferris (The Red Limit) 1982 |
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None whatsoever, it turns out. I was relying on my memory, but a couple of searches in the forum have convinced me that my recollection could not have been more wrong. I guess I must have mixed up your criticism of Occam's Razor with criticism of falsificationism.
My apologies.
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"A witty saying proves nothing" Voltaire. "All your bias are belong to us" Ara Pacis. |
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Ken, when you write that science 'is justified by how it accomplishes its purposes', do you mean that the method used by science is what justifies it? (I initially understood it as meaning that science is justified by the fact that it accomplishes its purposes.)
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"A witty saying proves nothing" Voltaire. "All your bias are belong to us" Ara Pacis. |
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The point I was making is that science is judged by the accomplishment of scientific purposes, not just any purpose. I thought I was quite clear that simply providing a feeling of comfort was not sufficient to be considered a purpose of science.
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. Last edited by Ken G; 24-July-2008 at 02:07 AM.. |
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Practicing scientists and other rational people recognize that a theory that fails to conform to what is accurately and appropriately observed is at least somewhat flawed. The response to that recognition is to attempt to devise a more accurate theory. It does not mean that a theory, such as Newtonian mechanics, that is known to not be correct in all circumstances is abruptly tossed out and forgotten. However, it does mean that a new or proposed theory that fails to predict phenomena in a regime in which it was intended to provide accurate predictions ought to be abandoned or substantially revised. None of the current physical theories is "true" in the mathematical sense and all have been falsified in the same sense that Newtonian mechanics has been falsified. We know that quantum theory and general relativity are incompatible. But neither is about to be thrown on the rubbish pile. Other people, on the fringe, seem to interepret the ideal of falsification to suit their personal and immediate agendas. Because current theories are inadequate to describe all that is observed (for instance the notions of dark energy and dark matter are used to in an attempt to describe a state of current ignorance) they feel justified in discarding most, if not all, of mainstream physics and inserting their own ad hoc notions of how nature works. This is clearly an inappropriate and irrational application of "falsification." It is perhaps traceable to the use of falsification in mathematics, in which acceptance of a theorem is quite binary. A theorem has either been proved or not proved and any counter-example is enough to declare a hypothesis to be false. But mathematics is not science. Last edited by DrRocket; 24-July-2008 at 02:21 AM.. |
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. |
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That point is also quite relevant to the "sidebar" I'm having with Disinfo Agent.
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. |
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. |
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There's a part of this post of dgruss23's that I think is very relevant to this thread, but I'll bring it up in a separate post. |
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Before I continue, I want to make it clear that I have snipped parts of dgruss23's post to highlight an aspect of "falsify" that I am interested to discuss in this thread; let's keep discussion of CDM etc to the other (Q&A) thread. From the OP: Quote:
* as a hypothesis, CDM on galaxy scales may (or may not) be consistent with (lots of) good observations * as a theory (or part of a theory), CDM may be very useful, as a device for generating lots of really good new research ideas * as a hypothesis, MOND is surely falsified because it is in intolerable conflict with SR * as a phenomenological heuristic, MOND may be fantastic (what was it called? Milgrom's fitting formula?), and may spur lots of really good new research ideas. If the yardstick is "falsify", then maybe we need to dump CDM on galaxy scales, and we certainly need to dump MOND. But how useful is that? So, to paraphrase what I wrote in post#13, from what's in this thread (including dgruss23's post quoted here), it seems that "X (observations) constitutes a falsification of (theory/idea) Y" is neither an accurate description of what happens in science nor a useful guide to how to actually do science. |
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"Stupidity gets denser in a crowd" - Old Finnish saying. [My website and My BLOG] [Nimblebrain forums] |
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To continue a bit on this "falsifiability" issue (rather than the core "falsified" issue of the thread), I see the former as a crucial element of science, it merely means we need to distinguish what we might now falsify versus what is falsifiable in principle. They are both science, but two different "flavors" of science, with different goals. In terms of the unfalsifiability of "expansion of space", I think you have reached the wrong conclusion: you've concluded it is science anyway, but I would say that in fact you have put your finger on exactly why it is not real science to say that "space is expanding", that is merely one picture you can use to describe the real science. The real science is that distances are increasing, for whatever reason you like to picture that and is supported within the general theory that works (shrinking rulers works fine too, for example). I would call that a "pedagogy", a way to teach a theory that is not the same as the theory because it is not testable in the same way. The way you test a pedagogy is called a "final exam", the way you test a theory is called an "experiment".
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. |
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Do hypotheses get to be falsified? theories? ideas? concepts? models? laws? An experiment or observation may be quite clear-cut: Mercury's perihelion moves in this way (with stated uncertainties/error bars), the atomic clocks aboard the planes differed by this many seconds when they got back home, the A, B, C and D images of the distant quasar varied over time in this way, and so on. But how do these clear-cut results relate to GR (for example), or CDM? I think a good example is the Pioneer anomaly: analysis of the tracking data shows an unmodeled acceleration of {value and direction; uncertainties}. So something is a bit off, or odd ... but what? Enter hypotheses, which are very specific, quite narrow in scope, and as fully quantitative as we can make them - they provide clear guidance, or pointers, on what to do on Monday when we get to the lab, because they are eminently testable (albeit sometimes more in principle than in practice). As a general rule, the things to be tested first are what's in textbooks - on Monday you build models using standard physics. Suppose you've done that, written papers, chatted over coffee (or something else) at meetings, etc, etc, etc, and the day comes when models built on standard physics have all been ruled out; what then? Time to sketch some ideas for new physics? which will be severely tested in the crucible of your colleagues sharp minds (and, often, tongues) ... modify, re-state, get the idea torn to ribbons again, repeat. Maybe one day a theory emerges ... what then? Can we say that "neutrinos" were such a theory, from the 1930s? or is that too grand a word? Certainly neutrino flavours/oscillations were a theory long before 2001! Is MOND a theory? Is CDM a theory (non-baryonic CDM, whether collisionless or not)? Are 'gap fillers', or 'place holders' in some kind of limbo, neither hypotheses nor theories? extremely useful but not really falsifiable? They are undoubtedly convenient as shorthands, if nothing else! Quote:
Last edited by Nereid; 24-July-2008 at 05:09 PM.. Reason: fixed [ quote ] tags |
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The things I'd classify as not falsifiable are invisible elf types, or religious beliefs maybe. And I don't reject those sort of things, out of hand. They just get put in the nonscience bucket. PS: Smiley-free posting for the past **015** posts |
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I feel like a rather straightforward concept about the process of science is getting lost in all this discussion. And that would be the role that observations play in determining the fate of a hypothesis/model/theory/principle/law ...
In the context of what this thread was broken off from one starts to wonder if perhaps some people posting on this thread actually think that observations cannot rule out a hypothesis/model/theory/principle/law. Now I know that is not actually the case, but if this is supposed to be a discussion of the validity of what I said on the other thread, then the context is getting completely lost. When a hypothesis is proposed, it's usefulness as an idea comes not only from what it predicts should happen, but also from what it predicts should not happen. When observations are made to test the hypothesis, the scientist must ask if within the uncertainty of the observations do the observations: 1. Confirm the expectations of the hypothesis (hypothesis X says Y should happen and Z should not happen. Observations show that Y happens and Z did not happen.) 2. Fail to allow a determination of the expectations of the hypothesis (Y might have happened but we cannot be sure and/or Z might not have happened but we cannot be sure). 3. Contradict the expectations of the hypothesis (Y did not happen, and/or phenomenon Z that should not happen actually did happen). If #3 is what happens then you have a hypothesis that is in conflict with observations. If #3 is confirmed multiple times and there are no addendums that can be made to the hypothesis to turn #3 from a contradiction into a compatible result then it must be concluded that the hypothesis is not useful, incorrect, falsified, fails to match the real universe ... pick what you think is the most appropriate term. In the other thread I discussed observational results that I argued fall under category #3 above. I had rather expected that we might be able to have some discussion/debate as to whether or not others agree/disagree that those observations are in fact an example of category #3. Instead, the discussion has turned down the road of suggesting that a scientific hypothesis which is in direct conflict with observations, fails to make predictions that observations confirm, and cannot explain certain observations should nonetheless not be considered "falsified", or incorrect, or no longer useful. Moti Ben-Ari discusses falsification in his book "Just A Theory" which is a defense of science against creationists and others that attack science itself. He says the following things in his section on "Falsification as a Methodology": Quote:
It is my hope that perhaps some will engage in the discussion I expected to have as highlighted in green above.
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"The scientist who asks the right question reconnoiters a new patch of the unknown, and may, with luck, bring it within the constricted but expanding boundaries of the known." ~Timothy Ferris (The Red Limit) 1982 |
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I think the issue there is that most of us would rather discuss science in general, with applications to all aspects of it, rather than some specific application like CDM. Quite frankly, there are no aspects of CDM that give me a personal issue, though it certainly could be due to lack of knowledge of the observations on galactic scales that you refer to. However, I do have great issues with the way the process of science is often framed in various places.
The account above by Ben-Ari does nothing to alleviate my disquiet. He stresses two personal aspects of doing science, both centered on a kind of mental comfort or allegiance of some kind, as experienced by human scientists in the act of doing science. While those are both valid human limitations at doing good science that are worth pointing out, it is ill-advised to discuss them as if they defined the process, or represented it at its best. Instead, they are more like pitfalls to watch out for in the act of doing good science. So they leave unanswered the real question of what defines good science, and why has it been so successful to this point. I don't think either of the red highlights even touch on those issues. But one thing is abundantly clear-- a central and dominant role for the unbiased and openminded interpretation of the "voice of nature" is the crucial underlying theme in all good science. Whether that is framed in terms of "falsification" or "confirmation" or "mental effort" is all fairly irrelevant, compared to simply asking : does the primary motivation for some model or theory come from the way it helps us unify and comprehend in a useful way how things actually are, rather than how we'd like to imagine them or what will make a better press conference or what generates less cognitive dissonance to think about? There is no "magic bullet", no failsafe recipe, for answering that question, we simply have to step back and be as objective and clear-minded as possible and do our best to answer it. But the core question involves usefulness of a theory, not correctness (which is too black-and-white of a notion), and that is the main flaw in "naive falsification". |
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a) Science says that humans are causing global warming, and we'll be in trouble soon if we don't do something to counter it. b) Some religion says that global warming is actually a test to mankind's faith, and that we'll be saved by God in the end so long as we don't try to intervene, but we'll be punished with worse things it we try to do anything about it. c) A doomsday cult agrees that global warming will be the demise of mankind, but says we should embrace it, because it's a sign that the Rapture is at hand, and any interference will be pointless anyway. How do you choose between these three propositions? Which one will you believe, and why?
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"A witty saying proves nothing" Voltaire. "All your bias are belong to us" Ara Pacis. |
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There is no "magic bullet" to choose between those, it all depends on your goals. People who think that there is some "logical way" to prove that science gives you the "right answer" are sadly mistaken-- it is illogical to imagine such a possibility could flow from logic alone. Logic never gives you answers, it is a technique for manipulating axioms such that all the answers are already determined by the axioms and you are merely trying to ascertain the connections you don't recognize without the assistance of a logical procedure. Thus the goal of logic is to help you understand your axioms, not to know if they were the "right axioms". Insofar as your list above is really a list of axioms, not a list of results, there is no way to decide "which is right" unless such a test is expressly built in as one of your axioms. That's what science does, and what religion does not do, and that is by far their most important difference. Both lead to perceived benefits-- one leads to benefits that are by axiom objectively and repeatably testable, the other to benefits that may only be tested on a personal basis, or not at all.
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In mathematics one can and does work with something approaching "absolute truth". All theorems are carefully stated and are either proved or not and can be, via counterexample, shown to be wrong. But all scientific theories, at least all that exist at this time, are known to be only approximationss to the reality of nature. Unlike approximations that occur in mathematics, approximation in science are not always precisely quantified a priori. We know that Newtonian mechanics is less accurate than general relativity. Yet we use Newtonian mechanics in a myriad of situations, secure in the knowledge that it is good enough, without a mathematically pure definitioin of what "good enough" is. We know that Newtonian mechanics is "wrong" because we know that general relativity is better. But we also know that general relativity is probably wrong, because it is incompatible with quantum mechanics, and we don't have anything better. The point here is that falsifiability in science is not an absolute, at least as a practical matter and as actually practiced. Some things in science are more false than others. Science progresses as a series of successive approximations, and that fact is lost on many in the general populace. |
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But lest we get too hung up on the issue of accuracy, note that science is about more than just the error in the prediction. It is also about organizing information, and suggesting new avenues for study. A good theory does this as well, and if it does it well, larger inaccuracies become tolerable. We also heard that sometimes it's not obvious what aspect of the theory is causing the problem, perhaps some idealization was made in a theory that is otherwise quite good. As long as a theory is generating the right questions to lead to advancement and progress, it is doing its job-- and that may be more the issue that comes up in the context of CDM. In fairness, however, it would also seem true that slavish attachment to a particular way of thinking even after it has passed its usefulness is a pitfall to avoid as well (personally I don't see that for CDM, even on galactic scales, but perhaps I'm not privy to enough information on the topic).
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. |
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And so why shouldn't people "turn to other means" to obtain the truth? The rebelliousness you mention is mainly because of the perceived ethical consequences that ensue--not from science per se--but from the perceived ethical consequences of scientifically inspired metaphysical systems such as atheism, naturalism, and materialism. And since theory is underdetermined by the evidence, given the choice, should not one choose the more ethical alternative??? Naturalism says that what is real is just what the scientists say is real; and if there is one essential mark to science, it is the link between theory and observation. Obviously, that link does not merely consist of naive falsificationism. Nevertheless, naturalism looks only to science to say what is and how we know what is. Ultimately, this is a pragmatic stance. We choose naturalism not because there is a proof somewhere that naturalism is true; no, we choose naturalism because focusing on the link between theory and the stimulation of nerve endings seems to work better than the stimulation of the internal brain cells, as when one claims to "feel" that Jesus has just entered one's soul or whatever. Both are kinds of experience, however. So what makes science different from other epistemologies is not merely the connection between theory and experience--no, it is the connection between theory and a certain kind of experience having to do with nerve endings at the interface between one's body and the rest of reality--which no doubt in itself entails a whole bunch of metaphysical assumptions: but so be it! Quote:
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So is the TBL confirmed or falsified? That depends on one's choice of a null hypothesis--there is no clear cut answer. Quote:
Yet the TBL is very "messy". It's not that accurate (the worst residual errors range from up to 10% to 20%, depending on model chosen). Quote:
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Logic is the grammar of truth. Meaning and absolute certainty are incompatible, and profound meaning and absolute certainty are profoundly incompatible. The only thing intelligence is capable of is recognizing itself. Last edited by Ken G; 25-July-2008 at 07:24 AM.. |
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In Dreams of a Final Theory Weinberg has written an entire chapter entitled "Against Philosopohy", and a nice piece of logical thinking it is. And I find myself in agreemeht with Cicero's statement that "There is no position so ridiculous that it has not been held by some philosopher." This is not to say that there is not value in the thoughts of a select few of he better philosopohers, but the value in advancing scientific research is nil. And, no doubt someone will point out a great advance or two made by someone like Descarte, but I will point back and note that the advance was made in a time when one person could understand enough to advance more than one discipline and Descarte's contributions to science were made while he acted as a scientist. Coordinate geometry has been useful to scientists. "I think therefore I am" has really not produced much that is tangible. |
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