Mar 17 2016

Is Everything You Think You Know Wrong?

dino-asteroidDoes sugar make kids hyper? Has science proven bumble bees can’t fly? Does the average person only use 10% of their brain capacity? Are routine multivitamins good for you? Were the dinosaurs killed off by an asteroid impact?

It is often observed that when a fact is accepted uncritically because, “everyone knows it to be true,” it is probably false. The answers to the above questions are no, no, no, probably not, and it’s more complicated than you think.

The best way to drive this home for many people is this – think of the one area of knowledge in which you have the greatest expertise. This does not have to be your job, it can be just a hobby. Now, how accurate are news reports that deal with your area of extensive knowledge? How much does the average person know? Does anyone other than a fellow enthusiast or expert ever get it quite right?

The universal experience (according to my informal survey over many years) is that the general public is full of misinformation and oversimplifications about your area of knowledge. Now extrapolate that experience to all other areas of knowledge. This means that you are full of misinformation and oversimplifications about every area in which you are not an expert.

Further, it is difficult to appreciate your own level of ignorance on a topic about which you are ignorant. The Dunning-Kruger effect applies to everyone.

This realization should have a humbling effect. It should also have a motivating effect, to always dig a little deeper and not be content with superficial absorbed knowledge.

One question that emerges from this realization is – why? To answer this, first let me dispense with the false dichotomy of “right” and “wrong.” Some answers are simply right or wrong, but they are at the extremes of a continuum. Many answers are partly right, or right to a certain extent but the truth is more complicated. Some answers are not so much wrong as incomplete. The desire to say that something is right or wrong sometimes gets in the way of exploring the true nature of the answer.

For example, is it wrong to say that the Earth revolves about the sun? As far as that statement goes, it is essentially true. It is true enough for some purposes, such as having a basic concept of how the universe is put together.

However, the statement is not strictly true. The Earth and sun both revolve about their mutual center of gravity. That center of gravity point, however, lies beneath the surface of the sun, and so it is reasonable to say the Earth revolves about the sun, while the sun just wobbles as a result.

Is it correct to say that the dinosaurs were wiped out by an asteroid? This is a reasonable first approximation of the current scientific consensus. However, a scientific pedant would point out that birds are dinosaurs, and so what you really mean is that the non-avian dinosaurs were wiped out. Further, there is a viable alternate scientific opinion that volcanic activity contributed to, and may have even been a primary cause of, the mass extinction.

And even that is a massive oversimplification summarizing a complex scientific debate. How deep do you want to go?

Another way to look at it is this – there is a grade school answer, a high school answer, a college undergraduate answer, an expert answer, and an international thought-leader answer. The goal for anyone who wants to be right should therefore be to be correct enough at your level of understanding, but to appreciate that there are deeper levels, and to be pushing toward the next level deeper of understanding. Be humble and curious.

But we still have not addressed the question of why most common knowledge is more inaccurate than it should be (often to the point of being wrong). That is a complex question, but here is my attempt at a quick summary. It partly derives from human psychology, and partly from culture.

People have a desire for simplicity and control. This motivates them to boil down complex knowledge into bite-sized nuggets. This necessarily introduces inaccuracy. Further, reality is horrifically complex. A good rule of thumb is – it’s always more complicated than you think.

People have limited time and mental energy. Any one person can only ever scratch the surface of even existing human knowledge, and that knowledge is exploding. So we have to take shortcuts, oversimplify, and settle for decent approximations. Just don’t fool yourself into thinking this is definitive knowledge, or ignore the vast depth of knowledge that you don’t have. If you are going to settle for good enough, then be realistic about what that means.

This is why I think it is a good idea for everyone to strive to have at least one area of very deep knowledge. It could be anything, whatever strikes your fancy. This teaches you about the structure and depth of knowledge itself. At the same time I think it is helpful to have a breadth of knowledge. It’s interesting to think about what the optimal pattern of knowledge is. I strive to have a basic understanding of everything, with areas of varying degrees of interest and expertise.

Culture also plays a huge role. Bits of knowledge (some might call them “memes”) spread through culture, and it is interesting to contemplate which memes survive and thrive. I do think there are selective pressures involved, and they seem to favor ideas and “facts” that speak to us in some way, that resonate, or reflect some fundamental idea, hope, or emotion. They don’t seem to favor accuracy and precision.

We love stories that are ironic, or are iconic of a belief, hope, or even fear. Sometimes they rise to the level of urban legends, but these are just the extreme examples. This is what filters down to the public consciousness. We might call this passive knowledge. It is what comes to you through your social network (which has now been vastly increased through both traditional and now social media).

A good rule of thumb is to be suspicious of all passive knowledge, for the reasons I stated above. You need to follow up with active knowledge, looking for reliable sources for confirmation and analysis.


The end result of psychological and cultural factors is that most of the common knowledge floating around is highly inaccurate or misleading, often to the point of being simply wrong.

Appreciating this situation is helpful and even empowering. The adaptive reaction to this realization is to be humble before the depth of your own ignorance. To be suspicious of all passive knowledge. To be aware of your own psychological biases. And to be curious enough to seek more accurate and deeper knowledge.

You might summarize all of this by saying – be skeptical.

28 responses so far

28 thoughts on “Is Everything You Think You Know Wrong?”

  1. mumadadd says:

    Thanks, Steve. This sort of stuff is really useful.

  2. MikeB says:

    How concise. How relevant.

    This might enter my syllabus this semester.

  3. LittleBoyBrew says:

    It is this stuff exactly that makes my life hell. Whenever I am asked a question I find myself prefacing my comments with statements such as “while I have not independently confirmed this fact, a blogger that I respect said…”, or “I read one study which said x but I know it is a complicated subject and therefore I would look for more info…”, etc.

    Basically, I am now a walking disclaimer. Thanks, skepticism. Thanks a lot.

  4. jt512 says:

    The Dunning-Kruger effect applies to everyone.

    Is that really true? It seems to me that Kruger–Dunning is like Asperger—a spectrum that most people show little-to-no sign of, and among those who do, there’s a huge a range of severity.

    This is why I think it is a good idea for everyone to strive to have at least one area of very deep knowledge. It could be anything, whatever strikes your fancy. This teaches you about the structure and depth of knowledge itself.

    That’s an interesting point. When I was an undergrad, I resented that I had to major in something, because what I really wanted to do at the time was to take the 101 class in, like, every subject. I couldn’t understand what the point was in having to specialize in something, but I think I agree with you on this.

  5. jt512 says:

    Thinking a bit more about this, it occurs to me that the worst Kruger-Dunning cases I have encountered were people with doctorate degrees, so I hypothesize that gaining deep knowledge in one subject area can actually exacerbate Kruger-Dunning tendencies in susceptible individuals.

  6. mumadadd says:

    “Basically, I am now a walking disclaimer. Thanks, skepticism. Thanks a lot.”

    Yup, that sounds about right. 🙂

  7. Teaser says:

    Favorite practicing physician quote:

    “Don’t confuse the results of your Google search with my MD”

  8. Willy says:

    Spot on. Two areas of interest for me are cooking (eating!) and gardening. I’ve learned over the years that both are riddled with “wisdom” that ain’t. I’ve even formed tidbits of information on my own that were “true”, yet discovered later that I was wrong.

    In my broader life, I’ve learned to caveat almost everything unless I “know” something fer shure, fer shure, Valley Girl. I slip up on occasion, maybe even too often, but I’m getting better every day. Nonetheless, I don’t think I’ll make it to perfection before the Grim Reaper strikes.

  9. Willy says:


  10. mumadadd says:

    Willy, you might like an episode of the ‘Inquiring Minds’ podcast, in which they interviewed Kenju Lopez – he’s a chef with a scientific bent. He talks about a lot of the “received wisdom” in cooking, and has put much of it to the test in a rigorously scientific manner.

  11. lagaya1 says:

    But will a frog really stay in a pan of water until it boils him to death? Skeptical minds want to know.

  12. BBBlue says:


    “Is that really true?”

    Even if it isn’t, it would be a good motto to live by.

  13. Willy says:

    mumadadd-Thanks–I listened to that just yesterday. I picked up his book from the library and will likely buy it.

    On the subject food, it was shocking to hear that Christopher Kimball left America’s Test Kitchen!

  14. mumadadd says:

    Willy, I might ask you to recommend some podcasts for me at some point, as we seem to have the same taste.

  15. jt512 says:

    @BBBlue: Better to actually understand the limitations of one’s knowledge.

  16. Robney says:

    Maybe ‘common knowledge’ could be described as cultural heuristics.

    ‘Common knowledge’ is generally close enough to an approximation of truth most of the time that it has some value even if it can often mislead us into holding assumed truths.

  17. Willy says:

    Mumadadd–The other two that fit with SGU are Thinking Atheist and Talk Nerdy, which you likely listen to already. Other than that, I listen to some gardening and cooking ones irregularly. Between podcasts and The Great Courses, plus reading, I’m jammed up. PLEASE don’t tell me about another good one–LOL.

  18. ccbowers says:

    Last I heard, Chris will be staying on ATK radio (therefore the podcast), but has left the company he cofounded after a contract dispute last Fall. He also left his position as editor-in-chief of Cook’s Illustrated magazine. Not sure if I’ll continue to get the magazines, but I guess I’ll see if the approach changes for the worse.

  19. Damlowet says:

    “Walking disclaimer” is an apt description of what I have become also. 🙂

    One area (to me) which seems to be riddled with “common knowledge” flaws, seems to be anything automotive! From how engines work, how aerodynamics work, how turbos work, why high octane fuel does ‘X’ ect ect. Very frustrating, very Dunning/Kruger.


  20. ccbowers says:

    mumadadd, “Kenju Lopez” I think you mean Kenji Lopez-Alt. I’m glad you brought that up, as I have not heard that particular interview. Thanks

  21. SteveA says:

    I like the stories behind the misinformation.

    Apparently the ‘We only use 10% of our minds’ meme grew from observations of early brain scans that showed only 10% of the brain was ‘lit up’ up at any one time.

    The important caveat ‘at any one time’ was lost (all the brain is used, but not all in the same instant) and the myth was born.

    The non-flying bumble-bee myth grew from a back-of-an-envelope calculation that compared the bee’s wing area to that of a light aircraft of the same weight. The aircraft would, in fact, be too heavy to fly, but the bee doesn’t fly the same way – it’s more akin to a helicopter…

  22. mumadadd says:

    Steve A,

    On the brain myth, I heard a different origin explanation recently. I’m not saying mine’s right and yours is wrong (not that I can remember exactly what I heard anyway, just that it’s not what you just said).

  23. mumadadd says:

    How ironic that the explanations for common misconceptions can also be common misconceptions… 🙂

  24. PeterElias says:

    Skepticism is the internal manifestation. Humility is also important.

    Evidence-based medicine sounds as if the evidence is both certain and durable enough to be the primary or even sole basis for action. That sounds perilously like dogma. My experience (38 years in primary care) is that the evidence is generally incomplete, often shaky, and always tentative. I think and talk in terms of evidence-INFORMED medicine. The evidence (such as it is) is information used in decision making. It should never be allowed to make the decision.

    The evidence is where I start the discussion with the patient, not where I end it.


  25. Damlowet says:

    @ PeterElias

    That’s exactly why Steve coined the phrase ‘Science based medicine’, because evidence can be extremely anecdotal, where science ‘should be’ rigorous and repeatable without ‘feeling’ or bias to skew results.


  26. Charon says:

    When mentioning the various levels of answers that can be given, it seems relevant to link to Asimov’s Relativity of Wrong ( ). Each level should be a better answer, but it doesn’t mean the lower-level answer is flat-out wrong.

  27. SteveA says:

    mumadadd: “How ironic that the explanations for common misconceptions can also be common misconceptions… :)”

    Thanks for the link.

    Irony indeed.

    I’m convinced I heard the ‘brain scan’ explanation on the SGU one time…but memory, who knows….

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