Appeal to Scientific Consensus is not an Appeal to Popularity or Authority

A common claim among various kinds of pseudoscientists such as creationists or climate change denialists is that appealing to scientific consensus is either an appeal to the popularity of a position or an appeal to an authority and that therefore, appealing to scientific consensus is a logical fallacy.

However, appealing to scientific consensus is not the claim that “the scientific community is an authority or that it is a popular position, and therefore correct”, but rather, there is an additional premise in the appeal to scientific consensus that does not normally exist in the average appeal to authority. To elucidate the difference, let us see how this plays out.

P1. There is a scientific consensus on X (evolution, global warming, HIV causing AIDS or whatever).

Now, had we gone straight from this to the conclusion that X is true, it would have been an argument from authority or appeal to popularity. However, let us not forget our additional premise.

P2. If there is a scientific consensus on X, then it is probably the case that X is a reasonable scientific conclusion supported by most different lines of converging evidence.

In general, the scientific community as a whole is very conservative in making strong statements, because as we all know, making categorical statements may come back to haunt you. So we can be reasonably sure that, in the majority of cases, a consensus position is at the very least support by most currently known evidence. It is easy to see how the following conclusion follows.

C. It is probably the case that X is a reasonable scientific conclusion supported by most different lines of converging evidence (from P1 and P2 by modus ponens).

Too be sure, the scientific community is not infallible or always right. However, when the majority of the evidence available supports a position, it is reasonable to hold it as a tentative conclusion regardless.

Emil Karlsson

Debunker of pseudoscience.

52 thoughts on “Appeal to Scientific Consensus is not an Appeal to Popularity or Authority

  • November 12, 2011 at 20:40
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    Sorry but premise two is VERY weak in this syllogism.

    The way you’ve justified it makes it sound even more untenable:

    “In general, the scientific community as a whole is very conservative in making strong statements, because as we all know, making categorical statements may come back to haunt you. So we can be reasonably sure that, in the majority of cases, a consensus position is at the very least support by most currently known evidence.”

    One may argue on empirical merit that the history of scientific consensus in validating scientific claims has been abysmal, and that historically, progress in science was often achieved through a break away from consensus opinions.

    I’d recommend at the least a rewording of premise 2, though that still won’t resolve what is a glaring formal weaknesses in this syllogism.

  • November 12, 2011 at 21:37
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    Thank you for your critical comment. From what I can tell, there are three main problems with your objection:

    1. My claim is not an historical claim, but a claim about the present. The scientific community is vastly different today than it was, say, 200-300 years ago. Therefore, historical counterarguments are inapplicable. Scientific consensus is not always right, but it is, for most of the time the most rational position (given the available evidence) to embrace. Thus, your objection confuses ontology (that which exists) with epistemology (what we can be justified about knowing about that which e. g. exists). See the “storm in New York” example below.

    2. Most historical revolutions in science, at least post-1800, has involved a modification of the consensus positions, not a complete rejection. For instance, Newtonian mechanics put humanity on the moon, despite the fact that it is an approximation to objects that are relatively slow with respect to the speed of light with sizes in between planets and atoms. Lynn Margulis theory of endosymbiosis did not refute common descent, just replaced trees with networks for early eukaryote evolution. Thus, far from showing the signs of radical paradigm shifts, a lot of cases in the history of science, at least post-1800s, turns out to be adding new onto old, detailing the limitations of the prevailing views and sculpting a new niche for itself, rather than the complete overhauling of the prevailing view.

    3. My argument was that a consensus position most likely reflected the current body of evidence, not that a consensus position meant that it is, in some global and absolute sense, true (with a capital T). In other words, my argument was that an appeal to consensus science was not an appeal to popularity or authority, since consensus positions in modern science are rarely established before strenuous testing and debate, which means that, probably, a consensus position is supported by the best available evidence at the time. That is the case regardless of whether the position gets modified in the future. This makes the consensus position and appeal to such a position, reasonable, even if it turns out, at a later date, to just be an approximation or even partly flawed. For instance, If I state that there will be a storm in New York in 2 years, I am probably wrong. But If I make this statement again each day, sooner or later, there will be a storm in New York precisely 2 years after my claim. However, just because I was, eventually, proven right does not mean that my belief that there would be a storm two years later was ever justified at the time I made the claim.

    As for rewording P2, I take it as self-evident from the context of my post that “evidence” should be understood to mean “the best currently available evidence” and P2 is a claim about epistemology, not ontology as by “reasonable scientific conclusion” does not mean true in an absolute sense, just well-supported by the currently available evidence.

  • November 13, 2011 at 18:23
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    Thanks for your reply.

    Much as I’d like to believe your arguments here, there remain many concerns.

    Some quick points:

    1. I did not intend to infer that your claim was historical, more that historical evidence can be used to undermine your second premise.

    2. Admittedly scientific breakthroughs have rarely arisen from “completely” rejecting the contemporary consensus – this was not the point I intended to make, so I apologise if I wasn’t very clear. However, it would be indefensible to deny that they have often occurred at the cost of deeply upsetting, and overturning many aspects of the contemporary status quo. For example, the shift from geocentrism to heliocentrism, Newtonian physics to Einstein’s theories of general and special relativity; not to mention the current situation with quantum theory that even challenges the very foundations of classical logic and the principle of causality.

    These few examples are clearly more than “mere modifications” of the status quo, so I find your argument here difficult to rationalise. The case could therefore be made that giving weight to appeals to consensus, rather than addressing revoutionary arguments and theories on intrinsic, formal rational or empirical merit, would result in scientific progress being stifled.

    3. Much as we’d like to be idealistic regarding the honesty and accuracy of scientific consensus, there are many instances in which creedal, political or financially-motivated vested interests have sought to prevent or withhold progress on non-scientific grounds; for example in the well-documented instances of the politicisation of science within the past century; or more famously in the creedal opposition to Galileo’s discoveries.

    If you believe I’ve misunderstood any points, I’d be happy to read any feedback you may offer.

    My regards.

  • November 13, 2011 at 19:57
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    Thank you for your illuminating reply. I will do my best to address them.

    1. The claim is now about how science has worked in the past, but how it works now. Therefore, historical counterexamples (such as heliocentrism) are, at best, criticism of a scientific community that no longer exists. In fact, in the specific example of heliocentrism, debates between heliocentrism and geocentrism occurred in Ancient Greece, but the stifling influence of biblical and Church authority, rather than the scientific community per se, enforced heliocentrism as a dogma.

    2. You are right that there are always certain aspects that are overturned, but in most of the examples you mentioned, such as general relativity and quantum mechanism, actually fit better with new modifications on an older structure, acknowledging that the earlier model was a successful approximation, but that it has to be modified in certain areas. Newtonian physics works really well at the level of every day life (we landed on the moon using pretty much only Newtonian physics). The predictions of special and general relativity cannot be empirically separated from the predictions of Newtonian mechanism at low velocities, since the gamma factor approaches 1, reducing relativistic mechanics to the Newtonian equivalent. When we talk about potential effects on causality by quantum mechanics, we are mainly talking about physical interpretations, not the mathematical model (i.e. mathematical handicraft to make predictions and solve problems) per say. There are several other interpretations besides the one put forward by Bohm (which is problematic since it depends on superluminal connections which is forbidden according to special relativity). The latest news about faster-than-light neutrinos should be treated with initial skepticism, because (pragmatic) truth in science is almost never decided by a single experiment, but by the independent convergence of evidence from many different lines of research. I think we should suspend judgement on that issue until the experiments are independently repeated by other research groups.

    You are absolutely correct in that appealing to consensus should not be the only part of the argument in favor of the consensus position. A discussion of the actual evidence and the flaws in the opposing case is a necessary part of the discussion as well. But my argument is not the ontological claim that consensus is always right about what the Truth (with a capital T) is, but the epistemic claim that, probably, most of the time, consensus is supported by the best available evidence and should be provisionally accepted, for now. Of course, future evidence may come along, or the current evidence may be reinterpreted in some ingenious way and overturned previously cherished beliefs, but that is no problem; we just change our minds. Science is, arguably, as much a method as a collection of facts and ideas. Whatever we loose in prestige by changing our minds when the evidence calls for it, we gain in intellectual integrity.

    3. You are again absolutely correct, but do not let’s forget that the same argument can be applied to the various positions opposing the consensus. Andrew Wakefield, the doctor who suggested a link between the MMR vaccine and autism (which has been debunked by over 12 large-scale epidemiological studies), profited from making that claim since he was paid by the vaccine injury lawyer Richard Barr. People who support so called complementary and alternative medicine likes to complain about large pharmaceutical companies making a profit, forgetting that alternative medicine is a 40 billion dollar industry per year in the United States.

    In general, I find the argument you provided in this third point, as well as my objection to that argument, to be of tangential relevance because we are both essentially appealing to motive, which is not necessary relevant to the truth of the claims being made by the person with said motive.

  • November 14, 2011 at 08:29
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    “The claim is now about how science has worked in the past, but how it works now. Therefore, historical counterexamples (such as heliocentrism) are, at best, criticism of a scientific community that no longer exists. In fact, in the specific example of heliocentrism, debates between heliocentrism and geocentrism occurred in Ancient Greece, but the stifling influence of biblical [sic] and Church authority, rather than the scientific community per se, enforced heliocentrism [sic] as a dogma.”

    I appreciate your explanation. However, this then entails that you qualify how and why it is that historic counterexamples are not relevant – a non-trivial undertaking that requires a comprehensive, systematic analysis of the history of science, among other issues.

    “You are right that there are always certain aspects that are overturned, but in most of the examples you mentioned, such as general relativity and quantum mechanism, actually fit better with new modifications on an older structure, acknowledging that the earlier model was a successful approximation, but that it has to be modified in certain areas. Newtonian physics works really well at the level of every day life (we landed on the moon using pretty much only Newtonian physics). The predictions of special and general relativity cannot be empirically separated from the predictions of Newtonian mechanism at low velocities, since the gamma factor approaches 1, reducing relativistic mechanics to the Newtonian equivalent.”

    Certainly, older scientific models are still of practical use within certain parameters, but I’m a little uneasy about using this point to justify that older models are a direct continuum of newer models in terms of their formal qualitative properties at a theoretical level. Is there more to this than I’ve understood here?

    “When we talk about potential effects on causality by quantum mechanics, we are mainly talking about physical interpretations, not the mathematical model (i.e. mathematical handicraft to make predictions and solve problems) per say.”

    I don’t quite understand this point. If you’re talking about mathematical models based upon probabilistic causality, then, to my knowledge, probabilistic causality was formulated reactive to perceived non-determinism in quantum phenomena such as virtual particles. I’m unsure though, given that this is not my area of specialty. I’d be interested to hear your opinion.

    ” A discussion of the actual evidence and the flaws in the opposing case is a necessary part of the discussion as well. But my argument is not the ontological claim that consensus is always right about what the Truth (with a capital T) is, but the epistemic claim that, probably, most of the time, consensus is supported by the best available evidence and should be provisionally accepted, for now.”

    Certainly, I understand your contention that the appeal to scientific consensus is the appeal to the best current evidence. The discernible problems I saw from the offset were:

    1. Defending this assertion, empirically – points which I appreciate your time in attempting to address.
    2. The practical utility of appeals to scientific consensus when evaluating new empirical knowledge that has yet to be incorporated into the consensus body of scientific knowledge – for which you provided the following explanation:-

    “You are absolutely correct in that appealing to consensus should not be the only part of the argument in favor of the consensus position.”

    The problem with placing additional requirements to an appeal such as this is that it may then be contended that it is technically an incomplete argument, and thus an informal logical fallacy on intrinsic merit. What other criteria do you consider would make this argument more supportable, and do you see any way of incorporating it into the body of the syllogism?

    “You are again absolutely correct, but do not let’s forget that the same argument can be applied to the various positions opposing the consensus. Andrew Wakefield, the doctor who suggested a link between the MMR vaccine and autism (which has been debunked by over 12 large-scale epidemiological studies), profited from making that claim since he was paid by the vaccine injury lawyer Richard Barr. People who support so called complementary and alternative medicine likes to complain about large pharmaceutical companies making a profit, forgetting that alternative medicine is a 40 billion dollar industry per year in the United States.”

    Surely this would only be a concern if an observer was to appeal directly to anti-consensus opinions? Criticism of appeals to authority or to consensus derive from ostensible weaknesses in any type of appeal to opinion (whether that opinion is idiosyncratic, popular or authoritative) without evaluating the intrinsic strength of the arguments- ie. it seeks to disqualify such appeals bilaterally in any discussion.

    “In general, I find the argument you provided in this third point, as well as my objection to that argument, to be of tangential relevance because we are both essentially appealing to motive, which is not necessary relevant to the truth of the claims being made by the person with said motive.”

    The claim I made was that non-scientific motivations do influence scientific consensus. If it’s your claim that scientific consensus = best evidence, wouldn’t this validate said appeals to motive? What do you think I’ve misunderstood here?

    Again, thank you for your time. My regards.

  • November 14, 2011 at 21:34
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    Thank you for your thought-provoking reply.

    i. The argument is that historical counterarguments are irrelevant since my thesis is not about how scientific progress or the scientific community worked in the past, but how it works in the present. These are arguably very different.

    ii. You can think of Newtonian mechanics as an enormously accurate approximation to situations with low velocities and fairly large objects (but of course, not too large; that would be the area of general relativity). The equations of general relativity and quantum mechanics reduces to classical mechanics in the areas where they both apply. In other words, classical mechanics can be derived from e. g. general and special relativity. It is therefore inaccurate to say that general relativity overturned Newtonian mechanics in a global sense, because Newtonian mechanics can be derived from it, and because Newtonian mechanics works extremely well in a broad range of every day situations, from dropping a ball from your hand to landing on the moon. A similar example can be found in quantum mechanics, where the discrete energy levels become closer and closer together as you move an electron away from the nucleus, easing nicely into approximately being continuous at larger levels.

    This principle is called the correspondence principle, which states that a new explanatory model in science must make the same predictions as an empirically very successful previous model in the areas where they are both thought to apply. In other words, there are very few instances where the Kuhnian notion of a radical paradigm shift applies, at least post 1800s. I could perhaps compromise and say that there are many more cases of this sort of extension and modification than Kuhnian paradigm shifts in the stated time period.

    iii. Basically, when it comes to quantum mechanics, even those interpretations that are claimed to be causal, cannot predict, say, the decay of individual radioactive nuclei. The thing that can be predicted (and determinist interpretations does not better than non-determinist interpretations here) is e. g. how long you have to wait before, say, half of the nuclei have decayed. Causal interpretations of quantum mechanics also violate a central principle of special relativity, namely that nothing can accelerate past the speed of light in a vacuum, because such interpretation require superluminal connections (more or less instantaneous communication through vast stretches of space that would require the information to travel faster than light), which makes these particular interpretations dubious.

    iv. The additional requirements are not for the appeal to consensus, but for pragmatic truth in science. That is, the best possible case for a scientific model is not merely “well, it is the current scientific consensus”, but arguments from evidence is also required, on top of that. Appealing to evidence and appealing to consensus are thus, in a way, complement each other, although, of course, evidence always wins. Notice that my claim is not that a position should be considered a provisional truth in science merely because it is the consensus position, but rather, that an appeal to scientific consensus is not intrinsically an appeal to popularity or authority, because modern scientific consensus is often based on the best available evidence, and as an extension, pragmatic truth in science should be based on an independent convergence of data from many different lines of evidence. This includes, but is not limited to, scientific consensus.

    v. You are, again, absolutely correct in that non-scientific motivations probably influence consensus positions (and scientific work in general). Nevertheless, this may be limited by the process of self-correction within science and the scientific community. This rarely exists in areas that we commonly term pseudoscience, as there is almost never any progress or internal self-correction. Also, the exact same argument can be made for the anti-consensus position. Non-scientific motivations probably influence that position, and those groups promoting that position, as well. Since most common anti-consensus positions (i.e. most types of pseudoscience) are probably relatively more influences by these non-scientific factors, the argument is stronger against anti-consensus positions. But at any rate, I am skeptical of this particular approach (both your argument, and the counterargument I just outlined above), because they are both fallacious in that they are appeals to motive. The motive of a person promoting a position, could be, but is not necessarily relevant to the truth of that claim.

    Have a nice day.

  • November 15, 2011 at 09:46
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    “The argument is that historical counterarguments are irrelevant since my thesis is not about how scientific progress or the scientific community worked in the past, but how it works in the present. These are arguably very different.”

    I understand your point here, but my concern was that you may be called upon to qualify how and why these two situations are different, and why these differences are relevant in the context of your syllogism. From what I can see, this does seem to complicate your argument somewhat.

    Thank you for your insight into physics, especially quantum mechanics. Though this is a field in which I’m not qualified, I found your ideas intriguing and motivation for further personal study. The only problem now, is the somewhat interesting irony that you seem to be arguing for the validity of indeterministic explanations of quantum phenomena, which is an epistemological shift from the prior baseline. The Einsteinian relativistic world view was also an arguably striking example of a Kuhnian shift.

    There are inevitably components contiguous with previous consensus views, in accordance with the correspondance principle, but I fail to see how it renders how significant a departure these ideas were, relative to the prior status quo. I agree that there are many more historical cases of gradualism in the progression of scientific consensus, but when these shifts in paradigm do occur, they are startling in significance and profoundly revolutionary to our broader understanding. To diminish their importance, on quantitative as opposed to qualitative criteria, seems somewhat alarming to me – tell me what you think of this.

    “That is, the best possible case for a scientific model is not merely “well, it is the current scientific consensus”, but arguments from evidence is also required, on top of that”

    I see how you consider appeals to scientific consensus as a means by which to amplify or accentuate specific empirical findings. This is probably something we all do as a matter of practicality in our respective fields. As it stands though, you seem to qualifying my earlier concern that the appeal to authority is intrinsically weak or fallacious. I apologise if I am continuing to misunderstand your point.

    Also, I didn’t explain all too well what I meant about the bilateral exclusion of appeals to opinion: The claim that anti-consensus opinions are more prone to non-scientific motivations only has relevance if one is asserting that appeals to the anti-consensus view are more valid than appeals to the consensus view. This is certainly not what I’m advocating, nor is it the formal basis for criticism against appeals to authority. The point is about focusing upon the arguments and evidence on their intrinsic merits, to the exclusion of any other noise.

    Poignant to pervasive methodological changes in my own field as of late, which have incidentally proven highly pragmatic, I would assert that the comprehensive, consistent, systematic “critical appraisal” of all relevant data is the gold standard by which to determine the best available evidence. Moreover, that introducing extraneous, potentially compromising, factors, such as arguments from consensus, risk the incorporation of unnecessary noise or bias into the decision-making process.

    I would be grateful for any feedback or criticism you may have.

  • November 15, 2011 at 20:21
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    Thank you for continuing to propose interesting and challenging objections.

    a) It should be implicit in the argument that scientific consensus refers to modern scientific consensus. There are many differences between the modern scientific community and, say, the way science looked in, say, the 1700s. The main difference is that the contemporary scientific community is much more focused on publishing in peer-review journals, working together as competing research groups, have better understanding of cognitive biases and common methodological pitfalls, reward overturning established notions, not as interconnected with religious or government authorities etc. There are so many different things you could point to here. I think this is really a non-issue.

    b) I am not arguing for indeterminist explanations per se; quantum mechanics is perfectly probabilistically deterministic (in the sense that we can say, with high confidence, that a certain number of nuclei will have decayed after a certain time). The problem is that we cannot predict, say, the decay of individual radioactive nuclei. But alright, let me grant you quantum indeterminacy as plausible candidate example of a Kuhnian paradigm shift (although obviously determinist descriptions in the form of Newtonian mechanics is still widely used and valid approximations in most everyday scenario). Although I would not say that quantum mechanics as a whole represent a Kuhnian paradigm shift because it can be thought of as a correction to Newtonian mechanics where the size of particles get very small. For the same reason, I would object to labeling Einsteinian relativity as a Kuhnian paradigm shift, because it can be thought of as a correction of Newtonian mechanics for high masses and velocities approaching the speed of light in a vacuum. Furthermore, one of the central postulates of special relativity is a form of Galilean relativity (also called Galilean invariance). This is the basic idea that the laws of physics are the same in all inertial frames. Naturally, there are unique and revolutionary principles in the theory of relativity, such as the speed of light as a cosmic speed limit, a speed limit no particle can accelerate past, but I would not go so far to say that the Kuhnian notion of paradigm shift fits better with either quantum mechanics as a whole or the theory of relativity for many reasons outlined above, such as (1) for most every day situations, Newtonian mechanics makes the identical predictions that the theory of relativity does and (2) you can land on the moon using nothing by Newtonian mechanics.

    c) Yes, an appeal to authority is fallacious, but my argument is that an appeal to the scientific consensus is not an appeal to authority, because it is probable that a consensus position is based on the best currently available evidence and that we therefore should provisionally accept such a consensus position, at least for now.

    d) Sure, critical appraisal is a great thing and should be applied everywhere in science. However, these kinds of terms are usually thrown around as a way to try and put pseudoscientific beliefs and arguments on the same level as well-supported science; compare with “teach the controversy” or “teach both sides” etc. It is also very easy to apply an asymmetrical skepticism in which the bar is sett much, much higher for established science than for contrarian positions. It should probably be the other way around, since the consensus position is, at least in many cases, arguably more probable with respect to the background information than a contrarian position. According to Bayes theorem, the less probability something has with respect to the background information, the stronger the evidence has to be for that position in order to rationally accept it. As Carl Sagan use to say “I believe the extraordinary should be pursued, but extraordinary claims [i.e. claims with a low probability of being true with respect to the background knowledge] require extraordinary evidence”. So in other words, some “biases” (although I would not say that using consensus as another argument in the overarching case is necessary a bias in an ethically negative sense) are not necessarily bad.

  • November 15, 2011 at 22:22
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    There are some notable errors in my previous post. They should be amended as follows:

    “There are inevitably components contiguous with previous consensus views, in accordance with the correspondance principle, but I fail to see how [it renders = this masks] how significant a departure these ideas were, relative to the prior status quo.”

    “As it stands though, you seem to [be] qualifying my earlier concern that the appeal to [authority => scientific consensus] is intrinsically weak or fallacious.”

    I’m a little concerned that you have based your criticism of critical appraisal on what appear to be assumptions. Moreover, even if what you state is true, it would be simpler to standardise the critical appraisal process, as has been implemented to great success in the field of medicine, than to eliminate the systemic problems associated with appeals to consensus.

    Though we remain disagreed regarding several key issues and though I believe a number of compromising weaknesses remain unaddressed, I think this discussion has progressed as far as it can in a dialectic capacity, at least in the short term – the key points of discussion are now being repeated.

    Again, I am very grateful for the time you’ve taken to respond to my concerns.

  • November 16, 2011 at 18:05
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    i. That is because the new ideas are mostly ideas that are more applicable (i.e. makes different, more precise empirical predictions) to minor areas where the previous model was not that well-supported. Although Newtonian mechanics can be derived from general and special relativity, we really only need to use the theory of relativity when masses are very large, or velocities are close to the speed of light in a vacuum. To be sure, the theory of relativity had many profound implications for how we view the world, but when it comes to the mathematical details, it can be viewed as something that can be saved and used only under special circumstances that are very different from the everyday world of fairly slow speeds and masses of trains and people.

    ii. The core of my argument for not viewing an appeal to consensus as a fallacious appeal to authority is that consensus is not correct just because they are an authority, but because if something is a current consensus position, then probably, it is the position that is most supported by the best currently available evidence. Naturally, this may change in the future as other evidence accumulates or are reinterpreted, but until then, the consensus position should provisionally accepted, not only because it is probably the most reasonable position to take at the moment (because it is probably based on the best available evidence), but it is also a position that can be used to make predictions and contrarians can test those predictions in hopes of falsifying them. Obviously, the “establishment” (if you will) have rewarded many Nobel Prizes to research that have undermined previously cherished notions.

    iii. Sure, standardization of critical appraisal is a great idea. I have no problem with that.

    While I do sense that you are right in terms of where this discussion is going, I would like to thank you for giving me a lot of food for thought. I am by no means an expert in analytical philosophy or the history and philosophy of science, so I may very well be mistaken in my arguments.

  • November 29, 2011 at 20:08
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    What intrigues me are your tag lines:

    “Modern life presents us with an apparent paradox: science has a strong cultural authority, yet primitive darkness is coming back in the shape of creationism, alternative and complementary medicine, opposition to vaccination, AIDS denialism and so on.This blog takes on the enemies of reason”.

    So you not only poison the well immediately, but you make the biggest appeal to modernity ever. Good job.

  • November 29, 2011 at 22:19
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    Thank you for your thoughts, although, for some reason, I seem to be detecting a certain level of irony in your comment. :p

    In any case, I do not think you understand the fallacy of poisoning the well. It is where opposing information about a person is presented in advance to an audience with the sole intention of discrediting or ridiculing everything that a person is about to say. Nowhere in my tag line do I perform this fallacy. Calling established pseudoscience for “primitive darkness” or “enemies of reason” is hardly controversial and is not meant to be a proof by assertion; in fact, I discuss the flaws in all of those positions in detail on this blog. The tag line is designed to be a short and clear mission statement, which by necessity probably will have to make use of some rhetorical flare if the goal is to be attention-grabbing.

    Also, “primitive” in “primitive darkness” should not be understood as the opposite of modern (as many modern things like quantum quackery is not reasonable, and many non-modern things are like willow bark that contains salicylic acid are not intrinsically bad), but rather resembling pre-scientific or anti-scientific attitudes (“primitive” on an intellectual level), regardless of them being modern or not.

    At any rate, if you do subscribe to any of the positions in the tag line, feel free to post what you think is the single most strongest argument in favor of said position and I will tear it apart in a later blog post.

  • June 24, 2012 at 20:09
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    “P1. There is a scientific consensus on X (evolution, global warming, HIV causing AIDS or whatever).”

    “P2. If there is a scientific consensus on X, then it is probably the case that X is a reasonable scientific conclusion supported by most different lines of converging evidence.”

    If P1 isn’t an appeal to authority, then P2 definitely is.

  • June 24, 2012 at 21:36
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    No, because P2 states that “there is a consensus on X” is just a proxy for “X is a reasonable scientific conclusion supported by most different lines of converging evidence”. So an appeal to consensus is not meant to state that consensus necessarily implies reasonableness, but rather that consensus is a strong predictor for reasonableness and can often be used as a stand-in.

    • December 1, 2012 at 23:48
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      Conformity can contaminate consensus to various degrees. The less hierarchical/political a discipline is, the higher the predictive value of Consensus would be. For example, Astronomy and Paleontology. A counter example is Medicine, where national and international authorities, as well as powerful financial interests, massively interfere. A few appointed officials, promoted to their highest level of incompetence and often linked to industrial interest, decide on the “consensus” treatment protocols to be adopted by the many by way of regulation or law. Not surprisingly, this discipline is credited with issuing the highest number of “denialist” labels of all.

    • December 2, 2012 at 16:42
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      You claim that “national and international authorities, as well as powerful financial interests, massively interfere”, yet you provide no evidence for this claim.

      You also claim that scientific consensus is decided by “a few appointed officials”, yet you do not bother presenting any evidence for this either.

      Why do you think that readers should take what you say seriously?

    • December 3, 2012 at 12:44
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      Let’s take the Netherlands, where I live, in as an example. The protocols for HIV treatment are prosed by a “core group” of clinicians, not scientists, appointed by the Dutch Association of AIDS Clinicians. Revisions are subject for comments to the members and to the HIV Association Netherlands. The latter is a non-representative patient group set up and sponsored by pharmaceutical giants Gilead, Janssen, Boehringer Ingelheim, Abbott, Merck Sharp & Dohme. These are the manufacturers of the meds recommended by the protocols. The circle closes nicely on itself.

      Consensus by compliance is evident in chapter 2.1 as well: 2.1. When to start?, where the automatic adoption of American guidelines (why not Canadian or English?), by virtue of authority, is announced.

      I don’t think authority and “revision by industry” are good predictors of scientific value in such a consensus, but I might be wrong.

    • December 3, 2012 at 17:06
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      Nothing that you have presented can be considered evidence for the claims you have laid out. Which HIV treatments work the best are of course decided by the scientific literature and professional clinicians. What you are talking about are guidelines set forth by professional organizations, not about scientific consensus per see. Thus, you are putting the cart before the horse. It is the consensus that informs clinical guidelines, not the other way around.

      The reason that countries chose to follow American guidelines is because the United States are at the forefront of research in this field.

    • December 3, 2012 at 18:20
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      “you are putting the cart before the horse. It is the consensus that informs clinical guidelines, not the other way around.”. Not quite. The medical literature decides nothing, it only provides arguments – clinical trials – for a consensus. Arguments can be rejected or accepted, so no consensus exists until it’s spelled out in the guidelines. The Dutch example illustrates the verticality of Medical consensus and the interference of commercial interests in it. I wouldn’t bet my life in the predictive value of this tainted process.

    • December 3, 2012 at 18:54
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      “The reason that countries chose to follow American guidelines is because the United States are at the forefront of research in this field.”. That’s an authority argument. The Dutch appointees “chose to follow” based on perceived US authority rather than critical disclosure of the scientific grounds. If every country does the same, we get universal consensus by authority. Not pretty for the patients.

    • December 3, 2012 at 23:27
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      Actually, the scientific literature does make decisions. This is because those positions that are supported by the evidence wins the argument in the peer-review literature. Then, scientists and clinicians use the mainstream scientific account to construct guidelines.

      Pointing out that the United States is in the forefront of research is not an appeal to authority. The reason that other countries model their guidelines after American guidelines is not because they are an authority per se, but because they are based on the best available evidence (which makes it an authority). So yet again, you put the cart before the horse.

    • December 4, 2012 at 00:21
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      Since I’ve duely addressed your objections and you’re just repeating what you had said, I won’t add anything else here.

  • December 1, 2012 at 23:19
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    Appeal to scientific consensus is mostly used in support of a “denialist” label. Here it’s clearly fallacious. Denial is the negation of truth, but scientific consensus changes over time, therefore the argument is irrational. It’s also a variant of “Argumentum ad baculum”. Because reputation as a denialist would harm most, it amounts to a threat on dissenters to conform. Even where this strategy adds fallacious support to a given scientific consensus, the attack doesn’t imply the consensus is wrong. But it increases the probability of low value in any evidence that requires this kind of approach in order to convince.

    • December 2, 2012 at 16:40
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      No, denialism is used her as a debating tactic, not as the opposite of truth. Thus, your assertion that it is an ad baculum fallacy falls apart.

      Furthermore, if you believe that reputation matters to denialists, then you are profoundly mistaken. Clearly, denialists lose much more credibility and reputation when spreading pseudoscience than being correctly labeled as denialists.

      It may be true that consensus changes over time, but this is something good, not a bad thing. That means that the scientific community updates and improve their positions and arguments in response to new evidence. Denialists typically do not.

      The claim that scientific consensus is flawed because it changes over time also contradicts the popular claim that the scientific community is dogmatic and does not update when new evidence arise.

      So which is it?

    • December 3, 2012 at 13:00
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      “The claim that scientific consensus is flawed because it changes over time” … I made no such claim. The flow is using a shifting standard to determine who’s a denialist and who’s not.

      Your claim that argumentum ad baculum falls apart because “they lose much more reputation when spreading pseudoscience” is tautological, because the claims “they are denialists” and “they spread psudiscience” are the same.

      The abundance of “denialists” within the discipline, which is huge in Medicine, should raise concerns about the methods used by the consensus to gain support.

    • December 3, 2012 at 16:58
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      Actually, you did make such a claim when you used the popular denialist assertion that “Denial is the negation of truth, but scientific consensus changes over time, therefore the argument is irrational”.

      A shifting scientific consensus does not determine who is a denialist and who is not. As have been pointed out to you before, denialism is a debating rhetoric, not a position.

      My claim that denialists lose much more reputation for spreading pseudoscience than being labeled as denialists is not tautological. It is merely the claim that spreading pseudoscience makes you lose more reputation than people putting the label denialists on you.

      Your claim that the abundance of denialists should raise concerns is invalid. The amount of denialists says nothing about “methods used by consensus”.

    • December 3, 2012 at 18:31
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      “A shifting scientific consensus does not determine who is a denialist and who is not.”. OK, then if your criteria for denialism – pseudoscience, or whatever tautology you may conjure up – is not the lack conformity with scientific consensus, then what is it? Please, spell it out.

      The amount of denialists says nothing about “methods used by consensus”. I said “the amount of denialists within the discipline”. Good science has a lower probability of internal dissidence, and as the proportion of the latter increases, so does the probability of bad quality in the consensus-forming process.

    • December 3, 2012 at 23:22
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      You are just repeating your assertions and not addressing any of my arguments. Why?

      If you bothered to perform a simply search on this blog, or on Google, you would easily be aware of what denialism means: [url=http://eurpub.oxfordjournals.org/content/19/1/2]What is Denialism?[/url].

      You are also wrong with respect to internal disagreement. Science thrives on internal disagreement and it is a key aspect of science. But don’t let’s confuse denialism for a genuine scientific debate.

    • December 4, 2012 at 00:19
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      “Science thrives on internal disagreement”. Ideally, but only when left alone. When hierarchy and commercial interests hijack granting, investigation, publication and regulation, no genuine debate can take place. The casef Medical science as we saw..

      “what denialism means”. According to the definition you link, denialism is:

      the use of false arguments when one has few or no facts to support one’s viewpoint against a scientific consensus or against overwhelming evidence to the contrary.

      Scientific consensus and “overwhelming evidence” are two ways of saying the same thing. So comparison against cientific consensus is the measure of who’s right and who’s wrong. I genuinely see no substance in your denial that “A shifting scientific consensus does not determine who is a denialist and who is not.”.

      You say “denialism is a debating tactic”. It it only if one knows to be wrong and purposely attacks consensus in order to deceive. But your claim works both ways: labeling dissenters as “denialists” is also a debating tactic. It consists in using a fraudulent consensus to discredit genuine whistleblowers that threaten a position of power and influence.

    • December 4, 2012 at 19:39
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      I refuted your claim that good science has a low level of internal disagreement and you literally have nothing to reply with? Shame.

      You still do not grasp the difference between opposing scientific consensus and denialism, despite being told the difference? Here is an easy way that I am sure even you will understand: a person could on defensible grounds object to a scientific consensus position without deploying the rhetoric and debating tactics of denialism.

      It is possible to incorrectly label someone a denialist, but like all labels, it is open for discussion. So what evidence do you have that e. g. what is usually labeled as HIV/AIDS denialism (or whatever position you are defending) is not a form denialism?

    • December 4, 2012 at 23:51
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      “…I refuted your claim that good science has a low level of internal disagreement…” You certaily haven’t thought about the implications for consensus of what you say. I’ll let the readers add 2 + 2.

    • December 5, 2012 at 00:38
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      I think the problem here is that you are confusing two very different kinds of debate; the legitimate scientific debate about various details with the non-existent debate about core principles that denialists claim exists.

      So there is no contradiction between the existence of a consensus with a legitimate scientific debate about details. Furthermore, consensus does not require 100% support (there will always be a few detractors no matter what).

  • December 5, 2012 at 00:49
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    “…consensus does not require 100% support (there will always be a few detractors no matter what…” Well, good science does NOT has a low level of internal disagreement (sic). You’ve reached a ded end, redefining consensus and all… I abandon, you win.

    • December 5, 2012 at 14:37
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      Actually, you are the one using the wrong definition of consensus. Let’s look at an arbitrary dictionary online, such as Merriam-Webster:

      Definition of CONSENSUS
      1
      a : general agreement : unanimity
      b : the judgment arrived at by most of those concerned

      So contrary to your view, consensus is not the same as 100% support. This is also easy to understand in practical terms, as there will always be dissidents no matter what the research question is.

    • December 5, 2012 at 15:42
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      “..So contrary to your view, consensus is not the same as 100% support…” red herring. Let’s look at your position and the contradiction. You claimed

      I refuted your claim that good science has a low level of internal disagreement.

      In positive form you say that good science has a high level of internal disagreement. But a high enough level of internal disagreement destroys consensus, so consensus is bad science and total lack of it is the best science.

      Well, I leave it to you to clean up your own mess.

    • December 5, 2012 at 18:24
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      You keep accusing me of logical fallacies, but you clearly do not understand them.

      No, the falsehood of “good science has low levels of internal disagreement” is not the same as “good science has a high level of internal disagreement”. There is a middle position that you are forgetting, namely that good science has a moderate level of internal disagreement.

      In other words, your position suffers from black and white thinking. So it is entirely possible for a consensus to exist in the sense of broad agreement about the main points, such as common descent, that HIV causes AIDS, that humans contribute a lot to global warming etc., but still have a moderate internal debate about the various details.

    • December 5, 2012 at 19:20
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      “…There is a middle position that you are forgetting…”

      Ah I see! A middle position…. Full consensus is bad science, no consensus is also bad science, and YOU determine what level of dissidence characterizes good science. So you’re always right in your judgement and you argument is non-falsifiable.

      Such is the untenable position of denying that good science is the one that achieves the highest possible internal consensus.

      It amounts to denying that Consensus is achieved by the weight of the evidence produced. Which amounts to acknowledging other means, different from evidence, of achieving Consensus. What are they, Groupthink? Ad Baculum?

    • December 5, 2012 at 20:37
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      Your claims are very confused.

      I have never claimed that I personally decide what is good science.

      What I have explained to you is that consensus requires the bulk of the scientific community (not necessarily 100%), that disagreement about details is important and that such disagreements will always exist.

      These are very simple points that are easy to understand. Yet their impact escapes you. This leads me to conclude that you are not really interested in a productive conversation. If so, why do you keep posting comments on this blog that lack intellectual substance?

      Why should I continue to humor your presence?

    • December 5, 2012 at 21:28
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      You’re the owner of the blog, if you feel you lose a debate you’re free to ban. Do what you have to do.

    • December 6, 2012 at 01:25
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      You just issued a ban threat, so your last argument was Ad baculum. Do you think I need say more?

    • December 6, 2012 at 17:46
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      Where did I use the term “ban”? That is your word, not mine. I merely asked why I should entertain your presence [by continue to respond to your comments]. So you are, yet again, abusing concepts like ad baculum.

      As far as I am concerned, you have said nothing of intellectual value in this discussion. So why should I continue to bother with you?

    • December 7, 2012 at 11:55
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      “…you have said nothing of intellectual value in this discussion…”

      Argument by assertion:

      “You have said nothing of intellectual value in this discussion. I say it’s true. Nothing you do can convince me otherwise. It is obvious to anyone. What I say is true. Oh, shut up and and admit it! Of course it’s true!”.

    • December 7, 2012 at 15:56
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      It is not an assertion, it is a conclusion based on your performance in this discussion so far.

      You are also being dishonest by putting words in my mouth and making it appear as if I said what you have put in quotation marks. I have not.

    • December 10, 2012 at 12:02
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      “…It is not an assertion, it is a conclusion…”

      Conclusions are preceded by a reasoning process, assertions are not, so you’re piling fallacy upon fallacy.

    • December 11, 2012 at 10:39
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      “..The reasoning process is this conversation….”

      Fallacy Argumentum Verbosum: “The reasoning of why God exists is the whole Bible…”

    • December 11, 2012 at 16:59
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      I think I have made it very clear that you a) do not know what you are talking about and b) do not know what the fallacies you are referring to mean.

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