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Scientific American

I Want to Believe

published July 2009 | comments (30)
Opus 100: what skepticism reveals about science
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Science begins with the null hypothesis, which assumes that the claim under investigation is not true until demonstrated otherwise. The statistical standards of evidence needed to reject the null hypothesis are substantial. Ideally, in a controlled experiment, we would like to be 95 to 99 percent confident that the results were not caused by chance before we offer our provisional assent that the effect may be real. Failure to reject the null hypothesis does not make the claim false, and, conversely, rejecting the null hypothesis is not a warranty on truth. Nevertheless, the scientific method is the best tool ever devised to discriminate between true and false patterns, to distinguish between reality and fantasy, and to detect baloney.

The null hypothesis means that the burden of proof is on the person asserting a positive claim, not on the skeptics to disprove it. I once appeared on Larry King Live to discuss UFOs (a perennial favorite of his), along with a table full of UFOlogists. King’s questions for other skeptics and me typically miss this central tenet of science. It is not up to the skeptics to disprove UFOs. Although we cannot run a controlled experiment that would yield a statistical probability of rejecting (or not) the null hypothesis that aliens are not visiting Earth, proof would be simple: show us an alien spacecraft or an extraterrestrial body. Until then, keep searching and get back to us when you have something. Unfortunately for UFOlogists, scientists cannot accept as definitive proof of alien visitation such evidence as blurry photographs, grainy videos and anecdotes about spooky lights in the sky. Photographs and videos can be easily doctored, and lights in the sky have many prosaic explanations (aerial flares, lighted balloons, experimental aircraft, even Venus). Nor do government documents with redacted paragraphs count as evidence for ET contact, because we know that governments keep secrets for national security reasons. Terrestrial secrets do not equate to extraterrestrial cover-ups.

So many claims of this nature are based on negative evidence. That is, if science cannot explain X, then your explanation for X is necessarily true. Not so. In science, lots of mysteries are left unexplained until further evidence arises, and problems are often left unsolved until another day. I recall a mystery in cosmology in the early 1990s whereby it appeared that there were stars older than the universe itself — the daughter was older than the mother! Thinking that I might have a hot story to write about that would reveal something deeply wrong with current cosmological models, I first queried California Institute of Technology cosmologist Kip S. Thorne, who assured me that the discrepancy was merely a problem in the current estimates of the age of the universe and that it would resolve itself in time with more data and better dating techniques. It did, as so many problems in science eventually do. In the meantime, it is okay to say, “I don’t know,” “I’m not sure” and “Let’s wait and see.”


Once an inferential or historical science is well established through the accumulation of positive evidence, however, it is just as sound as a laboratory or experimental science. For creationists to disprove evolution, for example, they need to unravel all these independent lines of evidence as well as construct a rival theory that can explain them better than the theory of evolution. They have not, instead employing only negative evidence in the form of “if evolutionary biologists cannot present a natural explanation of X, then a supernatural explanation of X must be true.”

The principle of positive evidence applies to all claims. Skeptics are from Missouri, the Show-Me state. Show me a Sasquatch body. Show me the archaeological artifacts from Atlantis. Show me a Ouija board that spells words with securely blindfolded participants. Show me a Nostradamus quatrain that predicted World War II or 9/11 before (not after) the fact (postdictions don’t count in science). Show me the evidence that alternative medicines work better than placebos. Show me an ET or take me to the Mothership. Show me the Intelligent Designer. Show me God. Show me, and I’ll believe.

Most people (scientists included) treat the God question separate from all these other claims. They are right to do so as long as the particular claim in question cannot — even in principle — be examined by science. But what might that include? Most religious claims are testable, such as prayer positively influencing healing. In this case, controlled experiments to date show no difference between prayed-for and not-prayed-for patients. And beyond such controlled research, why does God only seem to heal illnesses that often go away on their own? What would compel me to believe would be something unequivocal, such as if an amputee grew a new limb. Amphibians can do it. Surely an omnipotent deity could do it. Many Iraqi War vets eagerly await divine action.



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30 Comments to “I Want to Believe”

  1. epicurus Says:

    A very good 100th article! Two points though. One, contrary to popular belief, climate scientists have not yet proven anthropogenic global warming (see Warren Meyer’s paper available in the climate skeptic website). Two, I hold that science can answer the question what existed before our universe began, at least in principle. We don’t have a good answer at this time but we can formulate scientific theories and distinguish outright fantasies. As Mintzberg put it, theories aren’t true but they’re useful. On the other hand, fantasies aren’t only untrue, they’re not even false (non-falsifiable) and they’re not useful (don’t predict nor explain anything satisfactorily). Multiple universes and superstring hyperspace are scientific theories that may one day be proved or disproved. On the other hand, gods and supernatural entities are fantasies that cannot be proved or disproved even in principle. The null hypothesis gives them a probability of zero and Occam’s razor cuts them out of the possible theories because they are unnecessary and useless and unreal.

  2. L. K. Hahn Says:

    Regardless of whether global warming is anthropogenic, ocean acidification due to increased carbon dioxide has been documented; this alone justifies efforts to reduce atmospheric carbon dioxide.

  3. Dennis Skala Says:


    Why do you assume the status quo is optimal? Is a more acidic ocean definitely less desirable? Carbon dioxide levels have been many times higher than the current level in the past, and the earth managed to deal with that and survive. The same question is relevant to the earth’s temperature as well. My impression is that the AGW believers seem to think that 1985-1990 temperatures were ideal. Why so? In any event, before we spend a gazillion dollars and negatively affect a good fraction of the world’s population in an attempt to deal with a (probably) non-existent problem, I’d like to see a good cost-benefit analysis.

  4. bigterguy Says:

    Ocean acidification is simply the latest alarmist position.

    Even irrefutable proof of AGW would NOT justify significant efforts and costs to curb co2 – after all what is the ideal global temperature? And who decides?

    Pursuit of efficiency and conservation goals are, however, always welcome. But let the market dictate the extent to which people are willing to be inconvenienced for these goals. Government interference always makes a bad situation worse.

  5. Tommy Holland Says:

    I’m with you, Mr. Shermer. Count me in with those who are satisfied with the Unknown. I don’t trust my emotions enough to judge truth by them.

    More here

  6. Sarah Says:

    Congratulations Dr. Shermer! I love reading your column each month. I, too, am in awe of what I don’t know. Thank you for your continued work on behalf of science and skepticism.

  7. T.A. Schwartz, MD, MS Says:

    While the ultimate question of whether or not God exists, existed, may not be within the scope of science, surely the question of religion is. Every religion that I can think of, has God(s) interacting with us. I.e. “Visitations”, performing miracles, sending angels/prophets/demons/only son, ect. Applying historical science techniques, as mentioned in this article, are useful in critiquing religious claims.

  8. Steven Schafersman Says:

    epicurus says that “contrary to popular belief, climate scientists have not yet proven anthropogenic global warming.” True, nor have scientists proved the occurrence of evolution, the atomic nature of matter, or the existence of an objective, material universe. It’s a good thing that formal proof is not something that scientists do or are required to do (unlike mathematicians or philosophers who deal with logic). Scientists discover knowledge about external reality using various epistemologies, primarily empiricism, rationalism, and skepticism. Using methods based on these epistemologies–none of which necessarily require formal proof, although that is gratefully accepted when possible–climate scientists have demonstrated the overwhelming probability that humans are responsible for the current global warming (although many natural mechanisms were responsible for climate change in the past). The evidence and reasons for this are so overwhelming that it would be irresponsible–indeed, irrational–for anyone to deny it, especially politicians and AGW-denier commenters, who I see from their comments are now basing their objections to climate change on market forces and libertarian philosophy rather than denial of the scientific evidence. At least some progress has been made.

    By the way, multiple universes and superstring hyperspace are scientific hypotheses, not scientific theories. Let’s get the scientific terminology right as well as the scientific process.

  9. Greg "dglas" Teed Says:



    So, it doesn’t apply to all claims, after all. Please make the call. Or are skeptics only on the border of the “Show-Me state” skipping back and forward when it is convenient or expedient to do so.

    There are many, many more claims than just the existence of God that are in principle untestable. That some one is channeling spirits of dead people is one, or the spiritual healing of wounded souls, prophesies of always-future ends of times, or even something as simple and ubiquitous as any given normative claim. Worse, they can be created at will as a matter of mere stipulation. Are we to say skepticism doesn’t apply? Are we to say that no evidence is required for these? Are we to artificially limit the scope of skeptical inquiry to hold whole realms of claims immune to inquiry? Ridiculous.

    I cannot, with any intellectual honesty, artificially limit the scope of skeptical inquiry. Too much cognitive dissonance for me. Too much cherry-picking…

  10. Marc Blackburn Says:

    > Greg”dglas”Teed says: So, it doesn’t apply to all claims, after all. Please make the call.

    Your proposition doesn’t add up. If something doesn’t apply, it doesn’t apply; if it does, it does. This is not cherry picking, it is the reasonable application of scientific methods. You seem to be confusing skepticism with scientific proof. Skepticism can reach acceptable conclusions using only philosophical methods such as logic; scientific proof requires physical data. None of your examples – including the existence of God – are immune from skepticism, but each have a certain amount of invulnerability to proof. And that goes both ways, hence the need for skepticism.

  11. Greg "dglas" Teed Says:

    Am I the one confusing skepticism with scientific proof, Marc?

    Please read again. You’ll find that that is the very critique I am offering of Mr. Shermer. It wasn’t me, after all, who claimed, “Most people (scientists included) treat the God question separate from all these other claims. They are right to do so as long as the particular claim in question cannot — even in principle — be examined by science.”

    The examples I cite, including the one Mr. Shermer cites (god), are invulnerable to empirical proof and/or refutation specifically because they have been stipulated as such. A matter of mere definition. As you can, Marc, I do have some inkling of the matter.

    I look forward to the day Mr. Shermer ceases to believe weird things about my “metaphysical cloud chamber.” Perhaps as a skeptic, he will reconsider artificially limiting the scope of inquiry to protect the sacred cow – it doesn’t need protecting.

  12. sittingbytheriver Says:

    Nice article, Mike. congrats on reaching 100!

  13. Troythulu Says:

    As usual, Dr. Shermer, another interesting article, and it being your 100th, a milestone. Yet again, you articulate what nube skeptics like myself have been trying to say for years, but lacked just the right words to express properly. You manage to do this not just cogently, but entertainingly as well, a testament to your ability as a writer. Do us all a huge favor and keep at it. Your stuff is always a fun read.

  14. epicurus Says:

    There’s scientific proof (or evidence if that’s what you call it) for evolution, atoms and material universe. Who said science require formal logical proof? As for the overwhelming scientific evidence for AGW, please read Warren Meyer’s 80-page paper in the climate skeptic website. In the spirit of skepticism and the scientific method, try to answer the many questions raised there before claiming that AGW is already proven. This is neither irresponsible nor irrational. As you said, let’s get the scientific process right.

  15. MikeC Says:

    Michael says “But how can we tell the difference between what we would like to be true and what is actually true? The answer is science”, but I wonder if the overuse of words like ‘science’ and ‘scientific’ may be part of the reason why so many people believes so many bogus things.

    I guess ‘science’ is a pretty reasonable shorthand to refer to a way of examining nature via experiments and observations that is repeatable and subjected to a process of peer review …etc, and that loosely speaking its modern incarnation began around the renaissance. But perhaps every time someone bangs on about science, someone else goes away with the notion that its just one of many alternative truths.

    Afterall if your car isn’t working and you take it to a garage, the mechanic generally don’t make a distinction between mechanically fixing it as opposed to some other variety of fix. In the same sense the assumptions in an particular experiment and the conclusions drawn is either reasonable or not reasonable (or as reasonable as you can make it, subjected to available funding and/or subjects).

    I first had this notion in the mid ’90s when I saw a shampoo commercial that claimed the product was ‘scientifically tested’.

  16. Marc Blackburn Says:

    Greg “dglas” Teed Says: Am I the one confusing skepticism with scientific proof, Marc?

    I think so. Most scientists do take a non-confrontational approach to these beliefs, they are not in the business of busting people after all. Scientists are right to separate these claims from others because they are defined in such a way to be invulnerable to proof, not by the scientists, but by the believers. How exactly does one scientifically examine claims in which the only evidence needed is the mental impression that it is true? Dealing with these issues is a waste of their time.

    I think it is possible to prove God doesn’t exist – but not to a believer, and not at all if the definition of God excludes religion texts and doctrine, and shifts as easily as sand in a windstorm. Spiritualists also have ways to protect their beliefs, or themselves, from being proved wrong. They claim the mere presence of skeptics and any scientific apparatus keeps the spirits away. The best way to deal with these claims are to show how they COULD be done, but that doesn’t constitute scientific evidence of what DID take place. And besides, scientists are ill-equipped for the job. There is a reason why magicians and ex-con-artists are the experts in this.

    I don’t particularly care for Shermer’s position on the matter. He seems to think he can win people over by finding common ground upon which to agree. I find this a bit conciliatory, and see things more as Dawkins does. But nowhere does Shermer suggest skepticism doesn’t apply to any of the areas you cite, nowhere does he suggest skipping back and forward when it is convenient or expedient to do so. It is worth bearing in mind that some beliefs cannot be dispelled with any amount of proof, therein lies the difference between proof and skepticism.

  17. Anonymous Says:

    I agree with you, but I think that you fail to make a distinction where one is necessary – I think that the majority of fans of shows such as “The Twilight Zone”, “The Outer Limits”, and other sci-fi/fantasy anthologies obviously realize them to be fictional. The ones that the rest of the article seems aimed at people who watch (and believe) inexplicably popular shows like “Ghost Hunters International”, where they genuinely try to assert that the ghosts they ‘hunt’ are real, without providing any real justification other than furniture moving around and sudden drops in temperature that, if not being naturally occurring, could easily be manufactured by them.

    Just a clarification, since you seem to have lumped some of the good in with the bad.

  18. Greg&Marc R Lovers Says:

    I am a new subscriber, and it appears I discovered this site/magazine just in time for the 100th column. Cool. This was a fun read and I hope the next 100 are just as articulate.

    For so long I confused speculation and skepticism. Now that I have corrected my approach to discovering the truth about everything, I definitely feel more confident and armed for intelligent debates.

    By the way, you get a million Brownie points for the Simpsons reference in the beginning!

  19. jared Says:

    Why is there something instead of nothing?

    If you say that something has always existed (infinity) well then nothing could have just as easily always existed.

    This is the only question science cannot, even in theory, answer; and fittingly, it is the only real evidence for the existence of God.

    This ‘sublime awe of the great Unknown’ of which you speak IS God and the accompanying reverent attitude is central to any legitimate spiritual practice.


  20. David Says:

    I see a problem with relying on the null hypothesis as the skeptic’s final answer to anything paranormal. It is lazy. An example could be the near-death experience. This had been casually dismissed as silly nonsense by skeptics until reports of the experience continued to be documented. Finally some tried to examine these phenomena, finding a common thread in people’s experiences. If the out-of-body experience was a trick of the dying brain, or actually paranormal is not the real question. These were genuine experiences. Maybe because of nervousness concerning such topics, science was afraid to even consider it.

    The same could be said for the ghost experience. Ghosts have been a common human experience in history, mentioned in the Bible and in Shakespeare. Countless people have had these experiences. The actual experience is not a null hypothesis. It is real. The explanation for the event is a different story. But by dismissing these genuine experiences, we close our minds to what might actually be happening. Mere hallucinations, or is something else important happening? Pooh-poohing all paranormal is the lazy answer.

  21. Chris Howard Says:

    Beautiful! Thank you.

  22. PiotrK Says:


    Then, Mr Shermer, start believing :)
    At least one amputated leg has been healed: Miguel Juan Pellicer lost his leg after an accident in 1637 and got it back in 1640. AFAIK it is a well documented miracle.
    What do you think?

  23. Josh Scotto Says:

    @David RE: Out of body experiences and ghosts.

    Obviously Shermer’s asking for scientific proof. Who is going to provide that evidence? Scientists. People said, “Show me,” when referring to evolution, electricity, the atom, and whether or not the world is round.

    The idea that the null hypothesis somehow negates scientists from asking questions is silly.

  24. TrekGirl Says:

    @PiotrK: One anecdotal case from 370 years ago does not equal scientific evidence.

  25. Robert Says:

    I have a question. Using the scientific metheod can scientits prove that love exists?

  26. Josh Scotto Says:


    Yes they can. We can see which parts of the brain light up when people feel the emotion of love. One could make the argument that there is some sort of ethereal hippy rainbow love force floating around independently of our bodies but that’d take us right back to the null hypothesis and the burden of proof would be on the weed-blazing Trustafari.

  27. Otto Tellick Says:


    If by “love” you mean the strange, wonderful “tickling” sensation you sometimes (often?) feel in your chest when you look at your child or your life partner, this is presumably a physiological event, but considering our current tools and methods for scientific inquiry, trying to contrive the conditions that would be needed to record and measure this event objectively would be extremely difficult, bordering on inhumane or impossible. Still, anyone who has felt it knows that it happens. Those who haven’t felt it just have to decide for themselves whether the “inter-subjective agreement” among those who have should be accepted as sufficient evidence.

    If by “love” you mean the willingness to act primarily for the benefit of others, even when this will yield only a deficit (or at least no direct benefit) to yourself, it’s easy enough to prove the existence of such behavior.

  28. PiotrK Says:

    @TrekGirl: it is not an “anecdotal case”, but historically proven fact. History is not exact science – it’s based on documents and witnesses. There is a notarial act and documentation about thousands of witnesses.

    So, what is wrong with that case? The only thing, which is wrong, is that it does not fit the hypothesis that there are no miracles.

  29. Jay Says:

    The null hypothesis is wrong because it denies the existence of everything we don’t understand – or simply cannot yet measure. If we applied it to the past, we would have had to conclude that people were crazy for investigating magnetism, electricity, the strong and weak forces, etc.. It denies what cannot be explained or measured. But there was a time in which we could not explain or measure electricity or magnetism. N.H. would have forced us to believe these forces simply did not exist.

    There’s a fine line between blind belief, curiosity, and disbelief. When there’s evidence that something exists – but it still defies our attempts to explain or measure it. Then we should simply believe that something exists – but we cannot yet explain or measure it. I’ve seen evidence of “ghosts” first hand – enough to believe there’s something there. But I’m simply at a loss to explain it. There’s nothing wrong with acknowledging the existence of something you cannot yet explain.

    Think about it. If I came up with a drug that conferred immortality to 1% of the population, the FDA could not approve it because it only works on 1% of the population. The null hypothesis would prevent them from believing that immortality exists simply because it did not work 99% of the time.

  30. Benjamin Says:

    I have to give kudos to everyone who posted. After reading the article and thereafter the comments I have to tread back a good ways to remember where all of this began. Well done on 100. It seems that everyone here is aiming at a different bulls eye and defending it as though we were all shooting for the same star. This is good. This is excellent, and this is what makes humanity such a resillient artifact. Granted, in the scheme of our little blue rock we’ve only had a very limited scope to begin this great quest to define everything here and as much as we can in the incomprehensible universe beyond, but the steam that moves our human train starts with converstations such as this. Passionate disagreements fuel a search for truth that has many losers and few victors, but often the motivation to disprove seems relevant enough when people who perceive themselves so enlightened step beyond what is and into speculation. Let us not get caught up in some fraternal game of semantics when we are all searching for elements of the same truth. Our journey as a truth-seeking, scientifically particular species has only JUST begun; several hundred years of scientific inquiry is something to be proud of but truly a mosquito fart in the immense scope of time as we know it. Let us pat ourselves on the back with humility, and continue to challenge one another in our search for truth. And cheers to all for your excellent dialogue.