Apr 13 2009

Inductive Reasoning In Science

Recently I received the following question from an SGU listener named Marty:

I’ve been debating with a friend about the nature of science, and he brought up the following argument:

“1. All inferences from experience to conclusions about the future presuppose the principle that the future will resemble the past. (Principle of the Uniformity of Nature)
a. If we suspect that the course of nature may change and that the past is no guide to the future, then all experience becomes useless and does not support any conclusion about the future.
2. Therefore, no argument from experience can support the principle that the future will resemble the past.
3. No deductive argument can establish the principle that the future will resemble the past.
4. Therefore, the Principle of the Uniformity of Nature cannot be rationally justified.
5. If the Principle of the Uniformity of Nature cannot be rationally justified, then inductive reasoning in science cannot be rationally justified.
6. Therefore, inductive reasoning in science cannot be rationally justified. ”

Your thoughts?

This type of question comes up frequently – they essentially are attempts to use philosophy to argue that science cannot lead to objective truth, therefore science is not valid (or at least I can ignore it whenever I choose, which is typically how such arguments are applied). The problem with all such arguments is that science is not about objective metaphysical truth, but rather it is a collection of methods for making abstract models of nature and then testing those models against reality.

Inductive Logic

First a word on inductive reasoning, which is one of the types of reasoning in science (but not the only one). Induction is the process of going from the specific to the general, or forming a conclusion about the nature of the universe from a limited set of observations. One classic example is the fact that, so far, it has always been observed that the sun rises each day in the East. Therefore we can infer that the sun always rises each day in the East.

Induction is distinguished from deduction, which can be summarized as going from the general to the specific. If we take as a premise that the sun always rises each morning in the East, then we can deduce that the sun will rise tomorrow morning in the East. In valid deduction, if the premises are true then the conclusion must be true.

Induction is different – the observations may be true but because they are limited the conclusion may still be false. The classic example here is the observation that all swans ever observed are white, leading to the conclusion through induction that all swans are white. This was a reasonable conclusion until black swans were discovered in Australia.

Induction and Science

Science certainly involves induction, but it is not limited to it. But because much of scientific reasoning is inductive that has led to the philosophical question of how valid are conclusions in science. This is not a new question, and Marty’s friend would do well to investigate some of the extensive discourse on this question.

Philosopher Karl Popper had an interesting answer to this question – inductive reasoning does not exist, and therefore science is not induction. Rather he focused on verification and falsification. He argued that science comes up with hypotheses and theories that make predictions and therefore can be tested. He also noted that there is an asymmetry to this in that thousands of verifications cannot prove a theory correct, but one falsification can prove it wrong. Therefore the ability to be falsified is a necessary feature of any truly scientific idea.

This also means that no theory can be absolutely validated – only tentatively validated. Therefore science never arrives at absolute certainty. There may always be a black swan to be discovered out there. But scientific induction can lead to conclusions that have been validated to such a degree that we can comfortably act as if they are true. I don’t think anyone should waste any time or resources preparing for the possibility that the sun will not rise tomorrow.

Much time has also passed since Popper, and his ideas have been greatly extended. I will ignore for this post what I consider to be a huge diversion into post modernism but rather fast forward to a more contemporary vision of the nature of science.

While Popper, in my opinion, was essentially correct his view was incomplete. For example, science does not only consider one hypothesis at a time. Rather collections of theories are evaluated together over time by a community of scientists. Each theory must not only survive falsification it must also be consistent with other established theories – it must fit into the web of evolving scientific theories.

There are also other processes to consider in science, such as causal inference. Science does not just describe what exists or what happens in nature, it tries to explain how things happen – what causes what. For example, we may investigate genetic causes of the color of swans, or even the effects of various pigments on the absorption and reflection of various frequencies of light and how they affect the cones in our retinas.

Causal inferences often also require triangulation from multiple independent lines of evidence. Evolution, for example, cannot be established by one line of evidence, but requires many – the fossil record, genetic homology, developmental biology, population genetics, etc.

The Principle of Uniformity

The reasoning employed by Marty’s friend does not seem to take into account the actual nature of scientific conclusions. What they are saying, essentially, is that science does not yield philosophically certain truth – conclusions that must be true. This is correct but irrelevant, since that has never been part of science. Rather science comes up with models of nature and then tests those models. It retains those that are validated, but only for as long as they are validated, while continuing to try to falsify even previously validated ideas. It rejects or modifies falsified ideas. Scientists also try to infer causality in order to develop an increasingly complex abstraction of nature which makes predictions that can be further tested. And all the independent threads of scientific ideas must weave together into one seamless web.

The notion that there is temporal uniformity in nature – that the future will resemble the past, is not really a premise of scientific induction but rather one thread in the tapestry of science. It itself is a hypothesis that makes predictions and can be tested. For example, we have been measuring the speed of light very accurately for decades. If the speed of light were not constant and changed over time we could detect it. Therefore the constancy of the speed of light is falsifiable, but so far has been verified.

The same is true of all constants and laws so far discovered in nature. The laws of nature do not appear to change over time, and they also appear to exist throughout the universe. The principle of uniformity has been verified so far.

The only refuge for someone denying the utility of scientific induction and scientific reasoning more generally is to say that nature is so capricious and inscrutable that we cannot even reason about the principle of uniformity, or any other basic law or constant. However, such arguments, as the one above, generally take the form of using logic to demonstrate that science cannot reach conclusions that must be true – logically, 100%, metaphysically true. They then conclude that science is not valid, or “cannot be rationally justified.” But this is a false premise, because science has never been about logical truth, as I described above.

The real question is – is science pragmatically valid. Does it do what it claims to do. Here we have the metaexperiment of science itself. Over the last few centuries of formalized scientific investigation, what has science produced? If nature were inscrutable and the laws and constants that we infer from it of no utility, then science should not have progressed much or at all over the last few hundred years.

And by progress I do not mean just the ability to weave explanations of how the world works – any system can potentially do that. Rather I mean – has science given us an increasing ability to make predictions about nature that are later validated. Here the answer is clearly yes. If the principle of uniformity and all of our abstractions about gravity, mechanics, electricity, and the structure of the solar system were of no utility, then we could not send a hunk of metal from the earth and guide it to a distant planet and receive as reward stunning pictures of Saturn.

Conclusion

I may not be able to prove philosophically that the sun must rise tomorrow, but I can infer from observation and induction that it is overwhelmingly probable that the sun will rise tomorrow (and I can even predict when and where). As Stephen J. Gould wrote:

In science, “fact” can only mean “confirmed to such a degree that it would be perverse to withhold provisional assent.” I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classroom.

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34 responses so far

34 Responses to “Inductive Reasoning In Science”

  1. jblumenfeldon 13 Apr 2009 at 8:49 am

    Great post Steve – very clear and concise on a convoluted subject. It’s also one that seemingly will never go away, as the woo-woo crowd constantly tries out their tired arguments on another generation that hasn’t been exposed to philosophy 101 – or has been to the wrong philosophy class, or something.

    My personal favorites for further reading on this are Nelson Goodman’s “Fact Fiction and Forecast” – a classic of the genre who brought us the original “Black Swan,” though in his case it was a white crow, I believe. For those who really get into these things, WVO Quine’s paper “Two Dogmas of Empiricism” is about as seminal a paper as you can get.

  2. gfb1on 13 Apr 2009 at 9:23 am

    great post indeed; but, i had to laugh…

    [quote]I don’t think anyone should waste any time or resources preparing for the possibility that the sun will not rise tomorrow.[/quote]

    except for the chicken…
    :)

  3. DevilsAdvocateon 13 Apr 2009 at 9:37 am

    “If nature were inscrutable and the laws and constants that we infer from it of no utility, then science should not have progressed much or at all over the last few hundred years.”

    I dub thee Novella’s Principle Of Utility.

    In the ongoing debate between scientists and nonmaterialists, post-modernists, metaphysicians, et al, I sometimes get a little frustrated with the depth and complexity of the scientific arguments for the efficacy of science, feeling it too often arcs 45 degrees over the recipients’ heads. How much clearer and precise to simply state “it works”.

    Any argument or philosophy that would unseat science as the preeminent method for reliable, practical discovery must also explain why this ‘rationally unjustified’ method nonetheless works.

  4. oakidoon 13 Apr 2009 at 10:03 am

    This is exactly why mathematics is used to describe physical phenomena, and not the English language. You can convince yourself of anything provided your philosophical arguments and the concepts they rely upon are sufficiently ill-defined and vague.

  5. RickKon 13 Apr 2009 at 10:16 am

    Good post, Steve,

    I’ve had similar debates lately. And my argument always focuses on predictability. The strength of the scientific method is in its abilility to build predictive models. In the absence of an “absolute truth”, a near 100% accuracy of prediction is pretty good. The lack of utility of new age metaphysics or pseudoscience is because of the lack of predictability.

    And, to borrow from Tim Minchin, if there’s no utility in thinking the future will resemble the past, why then do Post-modernists bother to leave their houses from the ground floor. If experience and evidence count for nothing, why not just step out the second story window?

  6. tmac57on 13 Apr 2009 at 10:40 am

    It seems to me, that the premise that Marty’s friend put forth:”If we suspect that the course of nature may change and that the past is no guide to the future, then all experience becomes useless and does not support any conclusion about the future…” is an unwarranted assumption in the first place . You could not function in a world with such uncertainty . When you woke up in the morning, you might be afraid to put your feet on the floor because you couldn’t be certain that the floor was solid , or that it wouldn’t burn your feet, or that those feet were yours. We make millions of such common sense assumptions in order to make sense of our world, and most, but not all of them are reasonable.
    If the premise is unwarranted, then the conclusion:”then all experience becomes useless and does not support any conclusion about the future…” can’t be drawn logically, and points 2 through 6 are irrelevant .

  7. Mark Entelon 13 Apr 2009 at 11:10 am

    The college-style philosophical argument made me chuckle, because it reminded me of creationist arguments I have heard that try to account for the fact that light from stars billions of light-years away have had time to travel to Earth. One such argument is that light used to be a lot faster; not that I ever heard any warrant behind the claim, but it must be good enough as intellectual cover.

    I would note that we should not just ignore this sort of argument, though it is somewhat silly. When dealing with arguments/claims outside of common sense (like those I made while in college) I try to remember the lessons of John Stuart Mill. That if hard-fought truths & discoveries become merely received wisdom & dogma then they will cease to benefit us as much. Of course, if people continue to make the same incorrect argument time & again then they are just asking for it.

  8. TheBlackCaton 13 Apr 2009 at 12:04 pm

    Whenever I use the “it works” idea, I always get the response “that is technology/engineering, not science. I know technology/engineering works, but that does not mean science works.” I always respond that engineering is applied science, that technology is based off principles of science, but they always just deny this despite specific examples.

  9. superdaveon 13 Apr 2009 at 12:15 pm

    yet another post that makes me glad i never took a philosophy class as an undergrad. I think I would have had a perfect mold of my head in my dorm-room wall.

  10. artfulDon 13 Apr 2009 at 12:22 pm

    Causal inference. I’ve heard that term somewhere before. I think it it’s a reference to the mechanism that allows us to turn intuitions about causation into hypotheses that are unambiguous and testable. Thus enabling the further mechanism sometimes described as predictive inference. But I could be wrong, at least on style points.

    Seriously folks, that was a good post, and the reason I say that is because it really was a good post.

  11. artfulDon 13 Apr 2009 at 2:31 pm

    “a. If we suspect that the course of nature may change and that the past is no guide to the future, then all experience becomes useless and does not support any conclusion about the future.”

    This really doesn’t qualify as a premise, first or otherwise, because it’s begging a question which turns out to be circular and tautological. It already contains an assumption of what is to be proved, and is therefore fallacious.

    Since everything that follows depends on this assumption, the argument fails. (That’s what I would tell my students anyway.)

    The failing is not that of philosophy but of the particular “philosopher.”
    Logic is after all a philosophical construction. As is the scientific method.

  12. HHCon 13 Apr 2009 at 3:02 pm

    RickK, ” If experience and evidence count for nothing, why not just step out the second story window.” I think you have just explained the ending of the BBC version of “Life on Mars.” :-o

  13. CodeSculptoron 13 Apr 2009 at 4:14 pm

    The original position
    ” If we suspect that the course of nature may change and that the past is no guide to the future, then all experience becomes useless and does not support any conclusion about the future.”

    Is not a position that is supported by nature. If the course of nature changes at every instant, then clearly no predictions could be made, and all conversation would be impossible. Thought, life and the very continuing existence of matter itself is testament to some constancy of the “course of nature”…

    Further, if that clause were true, then the models of science itself would change to accomodate the changes in such a way as to proactively incorporate the changes.

    We know that the course of nature has been profoundly constant for at least the last dozen billion years.

  14. DevilsAdvocateon 13 Apr 2009 at 4:24 pm

    Of course, all constancies hitherto witnessed change once one is waiting on the microwave to ding.

  15. artfulDon 13 Apr 2009 at 4:56 pm

    CodeSculptor, my take on yours:
    Inductive logic is determinant of probability. The very form of the argument presented, aside from it’s failed premises, precludes any determination of certainty.
    We don’t really know that the course of nature has been profoundly constant, etc., but we don’t really need to know that to make probability assessments.
    And the so-called principle of the uniformity of nature is not a fundamental truth that meets the definition of a principal in any case.
    It’s neither testable or falsifiable as a universal or permanent proposition. So it does nothing that gets in the way of continuing to make successful predictions of the probable for the forseeable future.

  16. neokortexon 13 Apr 2009 at 5:46 pm

    Another great post, Steven I do love those little epiphanies we have when some set of ideas tie together in a nice coherent package. The argument of Marty’s friend is really a more advanced version of the typical rationale I hear when someone attempts to defend some weird belief X against a skeptically-based objection, which is “well science can’t explain everything.” At least Marty’s friend is not taking such an easy cop-out.

    It is also helps illuminate why religious and scientific explanations for natural phenomena are so profoundly incommensurate, something easily glossed over with attempts to shanghai the scientific (naturalistic) method into the service of some religious or supernatural framework–as in the case of your aforementioned Pillay. Then again it’s easy to understand why people are so damned resistant to a skeptical or scientific outlook, why so many prefer studying astrology over astronomy. It’s because they WANT metaphysical certainty–something which religion (including misc. New Age hokum) readily provides–or at least the illusion of it.

  17. pecon 13 Apr 2009 at 6:46 pm

    Why do you waste time on that? Science is a practical method that does not concern itself with absolute certainty.

  18. artfulDon 13 Apr 2009 at 7:04 pm

    pec, I would respond to that by pointing out that this was a really clever example of pretending to create valid inference by denying the consequent while at the same time affirming the antecedent.

  19. artfulDon 13 Apr 2009 at 8:02 pm

    I swear I didn’t see this document until just now, but the whole thing about Marty’s friend seemed a bit odd, so I googled and found the following:
    http://www.google.com/search?client=safari&rls=en-us&q=4.+Therefore,+the+Principle+of+the+Uniformity+of+Nature+cannot+be+rationally+justified.&ie=UTF-8&oe=UTF-8

    “Hume’s Argument that Inductive Reasoning in Science Cannot Be Rationally Justified (restated)

    All inferences from experience to conclusions about the future presuppose the principle that the future will resemble the past. (Principle of the Uniformity of Nature)
    If we suspect that the course of nature may change and that the past is no guide to the future, then all experience becomes useless and does not support any conclusion about the future.
    Therefore, no argument from experience can support the principle that the future will resemble the past.
    No deductive argument can establish the principle that the future will resemble the past.
    Therefore, the Principle of the Uniformity of Nature cannot be rationally justified.
    If the Principle of the Uniformity of Nature cannot be rationally justified, then inductive reasoning in science cannot be rationally justified.
    Therefore, inductive reasoning in science cannot be rationally justified.

    To solve a problem is to answer correctly the question(s) that it poses.
    To dissolve a problem is to show that it is not really a problem—i.e., does not pose any significant questions.

    The problem of induction poses the question: How should we respond to Hume’s argument?

    Possible Responses to Hume’s Argument:
    Premise 5 is false: inductive reasoning is inherently rational.
    Hume argument implies that inductive reasoning can be justified only on the basis of deductive reasoning.
    Premise 3 is false: the Principle of the Uniformity of Nature can be derived from the mathematical theory of probability.
    The inference from premises 2 and 3 to 4 is invalid: we have a priori knowledge of the Principle of the Uniformity of Nature.
    Since Hume’s argument says nothing specific about inductive reasoning, his conclusion can only depend on the fact that inductive reasoning is not a form of deductive reasoning.
    Premise 5 is false: inductive reasoning is a form of abduction (inference to the best explanation), which is rationally justified.
    The inference from premises 2 and 3 to 4 is invalid: we can “observe” necessary causal relationships and, therefore, know of their existence independently of deductive or inductive reasoning.
    The inference from premise 1 to 2 is invalid: neither of the two basic forms of reasoning—deduction, induction—can be defended in a non-question-begging way.
    Premise 5 is false: inductive reasoning can be modified so that the conclusions of inductive arguments say only that something is probably true.
    Accept the conclusion that inductive reasoning in science cannot be rationally justified. However, it does not matter because scientific reasoning is fundamentally deductive rather than inductive. (Popper) ”
    ***

    Yet ironically, Hume may have done the most to develop the concepts of causal inference.

  20. HHCon 13 Apr 2009 at 11:33 pm

    Dr., Was the Australian Black Swan Shiraz, Merlot, Cabernet, or a combination?

  21. pendens proditoron 14 Apr 2009 at 12:11 am

    It bugged me a little that a couple of your commenters were implying that this argument was just philosophical masturbation on the part of some nameless undergrad. As artfulD pointed out the argument was posed by David Hume. Eventually all philosophers are declared naive, but the argument was an important stepping stone in humanity’s path to a scientific world and is at least worthy of appreciation. When skeptics (commenters, not the author) are unknowingly scoffing at the words of one of the fathers of skepticism, well, maybe we should be hitting the books a little harder to avoid looking silly.

    And this is really only half of the argument. Hume’s question “can we know that the sun will rise tomorrow?” was followed with the answer “no we can’t, but logic isn’t why we believe it will anyway.” Hume is considered to be almost as much a psychologist as a philosopher, and in his arguments about beliefs being born out of habit — rather than being solely founded in reason — you can see where some of the seeds were planted that Popper eventually harvested.

  22. artfulDon 14 Apr 2009 at 1:08 am

    Some of those commenters were part of the posse commentatus here.

    And it’s hard to consider Hume as naive in the same sense that philosophers like Kant, for example, have come to be regarded. I suspect his use of logic was for the most part intuitive. My theories
    on that subject are somewhat controversial here, however.

  23. weingon 14 Apr 2009 at 9:02 am

    “I don’t think anyone should waste any time or resources preparing for the possibility that the sun will not rise tomorrow.”

    I don’t think it would be a waste to consider why the sun would not rise tomorrow and prepare for that possibility. I could think of the sun going supernova or an asteroid impact that would tilt the earth on its axis. If we had enough of a lead time for these events, we could do something.

    pendens,

    We can argue with Hume and anyone else. To avoid looking silly might prevent us from learning something. Looking silly may be the price of knowledge.

  24. neokortexon 14 Apr 2009 at 9:18 am

    Actually, pendens and artfulID, some of us (myself at least) spotted right off that the reasoning employed by Marty’s nameless undergrad friend was essentially Hume’s critique on induction, having read (and am reading now) Hume’s works and books about his ideas. I considered it too obvious to point out, to be honest, and commented on Steven’s post as it was given. Of course that may also be because Massimo recently reviewed this exact subject over at Rationally Speaking blog.

  25. lurchwurmon 14 Apr 2009 at 10:23 am

    “It is not the case that if God exists, then flies are insects”
    ~(P->Q)

    By DeMorgan’s Tautology, (P ^ ~Q)

    Therefore, by conjunction,

    “God exists” (P)

    and

    “Flies are not insects” (~Q)

    ;)

  26. Steven Novellaon 14 Apr 2009 at 10:33 am

    neokortex – thanks for the link to Massimo’s blog entry on this topic. I had not seen it.

    Yes, this is the classic Hume dilemma – which I guess I should have mentioned. Massimo goes more into the philosophy and spends less time on the solution, which I think I summarized adequately above. But I think his take is in basic agreement with mine.

  27. tmac57on 14 Apr 2009 at 11:20 am

    During Hume’s time ((26 April 1711 – 25 August 1776), his proposal of “If we suspect that the course of nature may change and that the past is no guide to the future” might have seemed more reasonable. But the history of science since then, has shown robustly that the course of nature for all practical applications is reliably consistent . To view it otherwise, as Gould said, would be “perverse”.

  28. lurchwurmon 14 Apr 2009 at 1:12 pm

    Hume’s skepticism of induction was well-founded as shown by Kant.

    Hume felt that at best we could create were “constant conjunctions” between an object and our experiences with that object. At least he was being honest enough so that we as a scientific community could understand how to rightfully approach our empirical knowledge when considered under the light of possible logical systems.

    Kant took it a step further and stated that we will never know objects in and of themselves, only the way that they appear to us under our personal sensibility. He even went as far as to create a logical system that accounts for logical truths that could be arrived at by any sensibility, logical truths that arise from human sensibility alone, and logical truths that transcend our sensibilities but are still dependent on the initial thought that they create.

    And even more disconcerting for mathematicians and scientists is that any time they try to show a model is internally consistent, some jerk comes along and shows it leads to a contradiction unless some other mathematical or logical system can intervene to account for the contradiction (or they just define the terms in such a way that the contradiction is side-stepped).

    With this in mind, science is still the strongest epistemological argument, because our minds are already ill-equipped to handle objective metaphysical truths (as shown by our models and limitation of sensibility), but with science, we at least keep gathering new data to allow possibility of building upon our sensibilities and refining our models. Without science, we would most likely would give up once our knowledge hit a contradiction (unless we were content with living based on contradictory knowledge).

  29. artfulDon 14 Apr 2009 at 1:44 pm

    And then that Categorical Imperative came along and turned out to be so much Kant.

  30. artfulDon 14 Apr 2009 at 3:32 pm

    Boiling down Hume’s argument here, it’s that induction is not deductively rational if you define rational as deductive. Therefor we need (by inference as he defines it) to rework the concept of rationality.
    Cutting to the chase, he then helped to bring us abductive reasoning, aka, abductive inference.

    “Inference is any act of deliberate assent, in any degree, however slight, which a man accords to a proposition because he thinks that assent warranted by his already accorded assent to another proposition or propositions, called the premises. It is one act of inference to adopt a hypothesis on probation. Such an act may be called an abduction. It is an act of the same kind, when a hypothesis is merely suggested as possible worth consideration. For even then some degree of favor is extended to it.” (‘Hume’s Argument against Miracles, and the Idea of Natural Law (Hume)’, MS 873: (Variant) 3, n.d.)

  31. YairRon 15 Apr 2009 at 4:53 am

    Excellent post as always, but I wanted to delurk to make two comments:

    1) Technically, our current measurement standards already assume that the velocity of light is constant, so they cannot be used to validate that assumption. However, people just use different standards when testing for its constancy.

    2) The principle of uniformity is a priori true because it is informatively empty. All it says, essentially, is that physics is looking for those aspects of nature which are universally regular. Since it doesn’t stipulate what these are, or even if there are any, the principle is trivially true. All that our experience can do is push such patterns to new heights of abstraction. For example, when we found out that spacetime is expanding we didn’t say the laws of nature change so that space expands – instead, we formulated new eternal laws that included the expansion. The question is therefore not whether the principle is justified, but whether it is practical – whether it is useful to describe nature via universal patterns. As Steven brilliantly showed, it is.

  32. Aaron Son 16 Apr 2009 at 3:10 am

    OK, post, but I’d avoid saying things like Popper being “essentially correct”. I do agree with the razor of falsifiability, but not the complete reject of induction.

    “But scientific induction can lead to conclusions that have been validated to such a degree that we can comfortably act as if they are true.” This assumes induction, such as the swan hypothesis being near-certain. I tend to accept induction in terms of probability/confidence, but I don’t know how Popper would view that kind of reasoning…

    “If the speed of light were not constant and changed over time we could detect it. Therefore the constancy of the speed of light is falsifiable, but so far has been verified.” This begs the question that the speed tests are correct, which goes back to assuming induction (that the test is valid) and the issue of which theory to reject. This tends to be an issue with Popper’s Critical Rationalism.

  33. HHCon 16 Apr 2009 at 3:44 pm

    Taleb (2007) The Black Swan states that WWI and 9/11 were unknown unknowns that were a great surprise and had enormous impact. But I say that they were unsurprising to those that were aware of the hostilities between nations prior to WWI and the powder keg of an assassination of the Arch Duke, just as pattern of Arab attack and training for terrorism was known to U.S. specialists who gathered information. The Black Swan theory is useless to explain reality as is the belief that there are only white swans in the world or that black swans only exist in Australia. Nature is more complex that academics conceive.

  34. [...] Reasoning In Science http://www.theness.com/neurologicablog/?p=517 Published by Steven Novella under [...]

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