Carl Sagan’s Baloney Detection Kit – an Analysis

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.

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.

excluded 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.