Pseudoscience criteria i.e. the criteria for sorting out real science from pseudoscience may be hard to tell though in practise we can usually see which is which. An important question to ask is “Does this stuff follow the scientific method?”

Fake science[]

Pseudoscience is literally fake science, and there have been many efforts to try to distinguish legitimate science from pseudoscience. Some efforts come from philosophers of science, but their discussions of the science vs. nonscience "demarcation problem" have not usually been helpful. One can sidestep that issue by interpreting pseudoscience as failed or flawed science and then attempting to distinguish between successful and failed science.

Irving Langmuir[]

American physicist Irving Langmuir (1881-1957) had delivered in 1953 a classic talk on what he called pathological science. He proposed these criteria:

  1. The maximum effect that is observed is produced by a causative agent of barely detectable intensity, and the magnitude of the effect is substantially independent of the intensity of the cause.
  2. The effect is of a magnitude that remains close to the limit of detectability; or, many measurements are necessary because of the very low statistical significance of the results.
  3. Claims of great accuracy.
  4. Fantastic theories contrary to experience.
  5. Criticisms are met by ad hoc excuses thought up on the spur of the moment.
  6. Ratio of supporters to critics rises up to somewhere near 50% and then falls gradually to oblivion.

He discussed

  • The Davis-Barnes Effect
  • N-Rays
  • Mitogenetic Rays
  • Allison Effect
  • Extrasensory Perception
  • Flying Saucers (now known as UFO's)

Although many mainstream scientific theories satisfy criterion 4 by being counterintuitive, they are accepted because they violate criteria 1 and 2, by being in good agreement with many observations and experiments, and also 5 by successfully accounting for seeming difficulties.

Martin Gardner[]

American science writer Martin Gardner had written a classic book on pseudoscience, Fads and Fallacies in the Name of Science (1952, 1957). He proposed these criteria for recognizing pseudoscientists:

  1. He considers himself a genius.
  2. He regards his colleagues, without exception, as ignorant blockheads.
  3. He believes himself unjustly persecuted and discriminated against.
  4. He has strong compulsions to focus his attacks on the greatest scientists and the best-established theories.
  5. He often has a tendency to write in a complex jargon, in many cases making use of terms and phrases he himself has coined.

Two years before, he wrote a short version of Fads and Fallacies, The Hermit Scientist for the Antioch Review.

John Baez and John Wilkins: Crackpot Indexes[]

Physicist John Baez Crackpot Index for pseudoscientific physical theories. You use it by adding the points for each criterion that its advocates satisfy. They range from

1 point for every statement that is widely agreed on to be false.


10 points for claiming that your work is on the cutting edge of a "paradigm shift".


50 points for claiming you have a revolutionary theory but giving no concrete testable predictions.

John Wilkins has created a biological version of it, The Evolution Crackpot index, which contains the likes of

10 points for each claim that Punctuated Equilibrium Theory, or some similar recent view in biology, is evidence of creationism (or some similar view such as Intelligent Design), or claim that modern biology is fundamentally misguided (without good evidence).


100 points for asserting that molecular evolution of complex proteins is impossible because of the large neutral gaps that selection would have to cross, or that there are boundaries between species or other groups of organisms that evolution cannot breach.

The Radners and John L. Casti[]

Daisie Radner and Michael Radner proposed in Science and Unreason (Wadsworth, 1982):

  1. Anachronistic thinking: returning to earlier, since rejected views without better reasons or responses to objections: flat earthers, creationism, etc.
  2. Looking for mysteries (as opposed to finding anomalies, e.g. Michelson & Morley's failure to measure the movement of the earth relative to the ether). (UFOs, Bigfoot, Bermuda triangle, rains of fish and frogs ...)
  3. Appeal to myths (Von Däniken, Velikovsky, creationism; Julian Jaynes?).
  4. Grab-bag approach to evidence: "Pseudoscientists have the attitude that sheer quantity of evidence makes up for any deficiency in the quality of individual pieces of evidence." Books on UFOs (anecdotal evidence), Bermuda triangle followers (distorted or fabricated).
  5. Irrefutable hypotheses. Creationism (world created as if it had been much older), parapsychology (Journal of Parapsychology: official policy to reject negative results for publication).
  6. Argument from spurious similarity (parapsychology, biorhythms).
  7. Explanation by scenario. (No appeal to scientific laws or principles; just a story or plot. Velikovsky, Julian Jaynes. But compare continental drift.)
  8. Research by exegesis. (Quotations from Ray Palmer, former editor and publisher of Flying Saucers magazine. Palmer quotes Admiral Richard E. Byrd, who flew over the North and South Poles: "I'd like to see that land beyond the pole. That area beyond the pole is the center of the great unknown"; "This is the most important expedition in the history of the world"; "That enchanted continent in the sky, that everlasting mystery." Creationists rejecting disavowals by authors of the creationists’ interpretation of pieces they quote.)
  9. Refusal to revise in the light of criticism.

John L. Casti is Paradigms lost: Images of man in the mirror of science (William Morrow, 1989), proposed a similar list:

  1. Anachronistic thinking
  2. Seeking mysteries
  3. Appeals to myth
  4. A casual approach to evidence
  5. Irrefutable hypotheses
  6. Spurious similarities
  7. Explanation by scenario
  8. Research by literary interpretation
  9. Refusal to revise
  10. Shifting the burden of proof to the other side
  11. A theory is legitimate simply because it's new, alternative, or daring

Bertrand Russell had a very good answer to that last one in An Outline of Intellectual Rubbish:

But if conformity has its dangers, so has nonconformity.

Some "advanced thinkers" are of the opinion that any one who differs from the conventional opinion must be in the right. This is a delusion; if it were not, truth would be easier to come by than it is. There are infinite possibilities of error, and more cranks take up unfashionable errors than unfashionable truths.


The number of possible errors eexcedes the number of truths, for example there are an infinity of possible gods but there can be only one true statement about which god actually exists or which gods actually exist. The true statement may be that no god or gods exist.

Robert L. Park[]

Physicist Robert L. Park has identified Seven Warning Signs of Bogus Science:

  1. The discoverer pitches the claim directly to the media.
  2. The discoverer says that a powerful establishment is trying to suppress his or her work.
  3. The scientific effect involved is always at the very limit of detection.
  4. Evidence for a discovery is anecdotal.
  5. The discoverer says a belief is credible because it has endured for centuries.
  6. The discoverer has worked in isolation.
  7. The discoverer must propose new laws of nature to explain an observation.

The last sign might seem to rule out any new theory, and Langmuir stated it better in his criterion 5 by noting the ad hoc nature of many pseudoscientific theories.

Sign 6 is a classic Hollywood stereotype of scientists, as Robert Park himself has noted. In reality, scientists have been successful because they work in groups, with different ones specializing in different fields, with them proposing different theories and checking each other's work and criticizing it. This has enabled science to be self-correcting, selecting out the successes and leaving behind the failures of individual scientists. Not all the time, but enough of the time to be a great success.

Wikipedia on Cranks[]

Crank (person) lists these criteria, working from several books on pseudoscience:


  1. overestimate their own knowledge and ability, and underestimate that of acknowledged experts.
  2. insist that their alleged discoveries are urgently important.
  3. rarely, if ever, acknowledge any error, no matter how trivial.
  4. love to talk about their own beliefs, often in inappropriate social situations, but they tend to be bad listeners, and often appear to be uninterested in anyone else's experience or opinions.

Many cranks

  1. seriously misunderstand the mainstream opinion to which they believe that they are objecting,
  2. stress that they have been working out their ideas for many decades, and claim that this fact alone entails that their belief cannot be dismissed as resting upon some simple error,
  3. compare themselves with Galileo or Copernicus, implying that the mere unpopularity of some belief is in itself evidence of plausibility,
  4. claim that their ideas are being suppressed, typically by secret intelligence organizations, mainstream science, powerful business interests, or other groups which, they allege, are terrified by the possibility of their revolutionary insights becoming widely known,
  5. appear to regard themselves as persons of unique historical importance.

In some technical field like mathematics or physics, cranks often

  1. exhibit a marked lack of technical ability,
  2. misunderstand or fail to use standard notation and terminology,
  3. ignore fine distinctions which are essential to correctly understand mainstream belief.

Further Comments[]

Some of these criteria deserve further discussion, especially criteria repeated by several authors. Numerous pseudoscientists have satisfied them, so we ought to take a closer look at them.

Excessive Skepticism[]

This is a common complaint of pseudoscientists:

To me truth is precious.... I should rather be right and stand alone than to run with the multitude and be wrong... . The holding of the views herein set forth has already won for me the scorn and contempt and ridicule of some of my fellowmen. I am looked upon as being odd, strange, peculiar. ... But truth is truth and though all the world reject it and turn against me, I will cling to truth still.

-- Flat-earther Charles Silvester de Ford in 1931, quoted by Martin Gardner.

There are a few cases where mainstream scientists have been unjustifiably skeptical, as with meteorites. Many eighteenth-scientists refused to believe that they were extraterrestrial rocks; they claimed that they were Earthly rocks struck by lightning and similar things. But on April 26, 1803, a meteorite fell on L'Aigle, France, and Jean-Baptiste Biot went to investigate. He found numerous independent witnesses and the appearance of very similar rock fragments. UFOlogists sometimes mention meteorites in this connection, evidently implying that skepticism about extraterrestrial spaceships is as unjustified as skepticism about extraterrestrial rocks.

There are also cases where scientists were skeptical for what had been good reasons. Continental drift is a good example. "Drifters" could not explain how continents moved, and their proposed mechanisms were very implausible. It was with the discovery of seafloor spreading that this conundrum was solved. The continents drift with neighboring oceanic crust, and oceanic crust is created in mid-oceanic ridges and destroyed in subduction zones.

However, skepticism about new theories is legitimate, because it helps sort out supportable theories from unsupportable ones. It helps keep scientists from being inundated from wasting their time on theories that turn out to be poorly supported if not worthless. For this reason, the burden of proof falls on advocates of new theories. Consider the theory that the Moon is made out of green cheese. One will only convince the scientific community of it by successfully demonstrating that the Moon is indeed made out of green cheese. One will not do so by demanding that mainstream scientists prove that it is not made out of green cheese.

The more clever pseudoscientists nowadays sometimes invoke Thomas Kuhn and his work on The Structure of Scientific Revolutions. Thomas Kuhn described scientific progress as going from one paradigm to another, with lots of "normal science" inside of paradigms, instead of a continual accumulation of new facts and successfully-tested theories. Not surprisingly, many pseudoscientists claim that their work represents some paradigm shift. But paradigm shifts only happen when many scientists conclude that the available evidence fits a new paradigm much better than an old one, and many pseudoscientists neglect that.

Many pseudoscientists go even further, claiming that they are being persecuted and comparing themselves to the likes of Galileo and Giordano Bruno. It is certainly true that the scientific community can refuse to accept their papers for publication, refuse to invite them to conferences, refuse to appoint them to professional positions, etc. The scientific community even forced Immanuel Velikovsky to change publishers by boycotting his original one. But that's not quite the same as forcing someone to recant, let alone burning them at the stake.

An interesting twist is that many pseudoscientists are strongly skeptical of rival theories, often showing a rigorous rationalism that they fail to apply to their theories. Martin Gardner experienced that with his classic book, with believers in Wilhelm Reich's orgone therapy indignant that he had discussed it alongside L. Ron Hubbard's dianetics, and believers in dianetics indignant about his discussing it alongside orgone therapy. Many such objectors objected to only one chapter of that book, finding the rest of it excellent.

Borderline Effects[]

Many pseudoscientists claim to observe effects at the borderline of observational activity or statistical significance. Martin Gardner once noted that many psi researchers' interest in statistical effects closely parallels many spiritualist mediums' working in darkness. In fact, Taner Edis noted in one of his books an inverse progression in psi research. In the late 19th cy., it involved research on ghosts and the like, then in the mid 20th cy., research on effects on decks on cards, then in the late 20th cy., research on effects on radioactive decay. The claimed effects became smaller and smaller, instead of getting greater and greater detail, as happens with mainstream scientific theories. Measurement accuracy improves, sometimes to extreme amounts, and upper limits get pushed farther and farther down.

Illogical Theories and Special Pleading[]

These are common in pseudoscientific theories. For instance, many psi researchers claim that the presence of skeptics impairs psi powers. They also claim that many people have "negative psi", and that psi powers often show a "decline effect" to the appearance of absence. Such considerations make psi hard to distinguish from non-psi.

It is true that many mainstream theories would seem to qualify, especially quantum mechanics. And quantum mechanics indeed started off as a very ad hoc sort of theory. However, quantum-mechanical predictions have not only been been successfully tested, quantum mechanics has been placed on a firm theoretical foundation.

Restoration of Older Theories[]

Many pseudoscientists see themselves as restoring older theories. Creationists are a rather obvious example. Physics pseudoscientists feature an interesting turnaround here. In the nineteenth century, they were often very anti-Newton. But their successors in the next century have often been anti-Einstein -- and they often claimed to be restoring Newtonianism. Perhaps related is how some pseudoscientists do a lot of interpretation of myths and legends. While they can indeed be legitimate sources, one has to be willing to recognize that some of them are not very good history. They can be origin myths or Just So Stories, and they can even be self-serving propaganda. In Livy's History of Rome, we find that after he mysteriously disappeared, Romulus briefly returned to assure a respected politician that the Gods intend for Rome to rule the world.

Perhaps not surprisingly, many myths and legends betray the level of knowledge of their tellers. Consider the story of Daedalus and Icarus, who fled Crete by making wings for themselves and flying over the sea. We now know that this will never work, because of the square-cube law. We are too big to fly in bird fashion; the heaviest flying birds weigh about 10 - 20 kg. Even if it was possible, what Icarus would experience is very different from the mythological version. In that version, as he flew upward, he got close the the Sun, which melted the wax in his wings, making the feathers fall off. What he'd actually experience is that the Sun would look the same size and have the same brightness, but the sky would get darker. The air would get colder and thinner, and Icarus would be telling himself "Brrrrr. It's cold up here." and "I can barely keep flapping, and I'm panting like crazy."

This article was originally at the Beacon Library (now defunct).