Astronomer Carl Sagan created a baloney detection kit that highlights common mistakes in reasoning that are used by manipulative predators to ensnare the unsuspecting. We’ve illustrated it with some fresh examples.

  • attacking the critic rather than answering the criticism (ad hominem argument):- Jones is a divorcee, so you can’t trust his opinion on anything.
  • bowing to authority:– We should believe what he says, because he has written six books; He is a priest, so there is no way he would molest a child.written 6 books baloney
  • adverse consequences:- If we don’t find him guilty, other people will commit the same crime.
  • appeal to ignorance—whatever has not been proved false must be true, or what has not been proved true must be false. Ambiguity causes cognitive dissonance or uncomfortable feelings:- Until there is evidence that UFOs don’t exist, we should believe they do, just in case.
  • special pleading—the attempt to rescue an illogical idea:- Shoplifters should be prosecuted, but not my daughter, because she just made one mistake.
  • begging the question—also called assuming the answer:- The death penalty discourages violent crime, despite statistics showing it is not a deterrent, and evidence that criminal psychopaths – who commit half of violent crimes – have no concern for the consequences of their actions.
  • observational selection—or the enumeration of favorable circumstances. Francis Bacon called this counting the hits and forgetting the misses:- I found a parking space because of my lucky rabbit’s foot, but I ignored its failure to protect me from a parking ticket.
  • statistics of small numbers—a close relative of observational selection:- They say that one out of every five people is Chinese, but I know hundreds of people, and not one of them is Chinese.
  • misunderstanding the nature of statistics:- President Eisenhower was surprised that half of all American citizens have below average intelligence.
  • inconsistency:- Build weapons to protect against the worst potential military disaster, but ignore scientific evidence of environmental dangers because they’re not “proved.”
  • non sequitur—Latin for “it doesn’t follow”:- Our plans will succeed because our leader is handsome; you will become a drug addict if you leave the group.
  • post hoc, ergo propter hoc—Latin for “it happened after, so it was caused by”:- Before women had the vote, there were no nuclear weapons, so nuclear weapons came about because women were given the vote.
  • with us or against us baloneyexcluded middle, or false dichotomy—considering only two extremes where there is a continuum of intermediate possibilities:- If you’re not part of the solution, you’re part of the problem; You’re either with us or against us.
  • short-term versus long-term—a subset of the excluded middle, but Sagan gave it special attention:- We can’t afford to educate or feed malnourished children, because we have to spend so much dealing with teen crime.
  • slippery slope— yet another form of the excluded middle:- If we don’t stop women from covering their faces in public, there will soon be suicide bombers everywhere.
  • confusion of correlation and causation:- A survey shows that more people with higher education are homosexual than those with less education – so, education makes people gay.
  • the straw man—caricaturing a position to make it easier to attack:- Evolutionary science proposes that that we are all just monkeys, so we needn’t listen to scientists.
  • suppressed evidence, or half-truths:- A “prediction” is reported, without explaining that it was actually made after the event. A war is fought based upon distorted and false information.
  • weasel words—where words are distorted to hide the truth:- “Collateral damage” attempts to justify the killing of civilians by dehumanizing them.

It is a good idea to think up your own examples, to better recognise these logical fallacies. The baloney detection kit was originally a chapter in Sagan’s fascinating book, The Demon-Haunted World. Sagan’s original baloney detection kit can be found here.

Carl Sagan, The Demon-Haunted World: Science as a Candle in the Dark, Ballantine Books, New York, 1996.