Various authors offer different criteria for distinguishing real from bogus or pseudo-science. Here are examples from two books:

Martin Gardner, Fads and Fallacies in the Name of Science

In his book Fads and Fallacies in the Name of Science, Martin Gardner offers a number of features as characteristic of "cranks." These are:

  1. "Cranks work in almost total isolation from their colleagues." Gardner points out that during the Renaissance genuine scientists might still be quite isolated: there were no journals or scientific societies, and there were social (especially religious) pressures against communication (witness Galileo and, much later, even Darwin).
        Cranks claim that their isolation is due to the shortsighted traditionalism of conventional science. (Here they might make use of Kuhn's point that scientific education resembles indoctrination in some important respects.) And they can point to examples of truthful claims which were scornfully rejected by mainstream science: hypnotic phenomena, Semmelweis' claim that doctors should sterilize their hands before delivering children, and the refusal of eighteenth-century astronomers to believe that rocks fell from the sky. "Reaction against medieval superstitions and old wives' tales was still so strong that whenever a meteor fell, astronomers insisted it had either been picked up somewhere and carried by the wind, or that the persons who claimed to see it fall were lying. Even the great French Académie des Sciences ridiculed this folk belief, in spite of a number of early studies of meteoric phenomena. Not until April 26, 1803, when several thousand small meteors fell on the town of L'Aigle, France, did the astronomers decide to take falling rocks seriously." Some stodgy traditionalism is useful for science (as Kuhn and Popper both point out).
  2. A "tendency toward paranoia." This is exhibited in five ways:

(It's interesting to note that in his book, first published in 1952, Gardner explained his failure to discuss astrology by writing that it "is so far removed from anything resembling science that it does not seem worth while to discuss it.")

Daisie Radner and Michael Radner, Science and Unreason (Wadsworth, 1982)

Radner and Radner suggest nine marks of pseudoscience:

  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 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.

Last update: January 13, 2000.
Comments? Email me at

Curtis Brown | Philosophy of Science | Philosophy Department | Trinity University