Slothful induction

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Slothful induction is a logical fallacy in which an inductive argument is denied its proper conclusion in spite of strong evidence. While skepticism is valuable, a slothful induction occurs when someone falls into pseudoskepticism and demands an unfairly high amount of evidence before accepting an idea. Often, slothful induction becomes a game of moving the goalposts. It is the opposite of overgeneralization.

The fallacy is an ad hoc fallacy and an informal fallacy.

Alternate names[edit]


  • Strong evidence suggests X results in Y.
  • In spite of this, someone insists Y was caused by something else.


A drunkard has had seven car accidents in the last seven months. Each time, the drunkard had immediately prior visited a bar. Each time, the drunkard tested positive for alcohol above legal limits. Each time, bystanders report that the drunkard's car had been acting erratically. It is strongly evident that the drunkard's alcohol causes their accidents. Yet the drunkard insists that it is just a coincidence and not his fault.

An example of slothful induction is when anti-evolutionists often ask for "proof" of evolution, and act triumphant when none is forthcoming. This is perfectly reasonable for science to do — after all, no scientist can even be certain of what evidence will come up in the future that may contradict the current theory. Yet those of the anti-science movement who cling to this detail usually fail to hear the words put in place of "proof" — overwhelming evidence.

William Dembski's Explanatory Filter is a good example.

Why it's wrong[edit]

To counter such hogwash that absolute deductive proof is required for the conclusion to be reasonable, one can use reductio ad absurdum. Take the statement "Gravity has always existed, so gravity will continue to exist." The conclusion ("it [gravity] will continue to exist") cannot be 'proved'; however, every time we observe the world, we see uniformity in nature, so it's reasonable to assume that gravity will continue to exist. If someone denies an inductive argument despite a large body of evidence, merely because induction can't "prove", then they can walk off a cliff.

See also[edit]

External links[edit]