LogicalMANIPULATIVE

Argument from Incredulity

What it is

Treating one's own inability to imagine or understand how something could be true as evidence that it is false — or, in the mirror form, that a preferred alternative must be true.

How it works

The form is: I cannot see how P could be so; therefore P is not so. Dawkins (1986) named it the argument from personal incredulity while answering a bishop who found the evolution of the polar bear's coat inconceivable; it is a species of the argument from ignorance (Walton 1996), with the speaker's imagination standing in for the state of the evidence. It persuades because incredulity is contagious and feels like insight: a confident “come on, that cannot be right” transfers the burden to the other side without offering a premise, and audiences mistake the speaker's certainty for knowledge. It is reinforced by the illusion of explanatory depth (Rozenblit & Keil 2002): people overrate how well they understand mechanisms, so an explanation they cannot picture seems suspicious rather than merely unfamiliar. The honest version is a real gap in understanding stated as if it were a gap in the world. The knowing version pairs incredulity with a ready alternative — design, conspiracy, fraud — so that the audience's discomfort is channelled into the speaker's conclusion. The tell is “I just cannot believe…” followed by a verdict rather than a question.

Real-world examples

  • •Dawkins (1986) quotes Bishop Hugh Montefiore's objections to natural selection, which repeatedly take the form “it is difficult to see how…”, and points out that the difficulty is the bishop's, not nature's.
  • •Behe's irreducible-complexity argument (1996) holds that structures such as the bacterial flagellum could not have evolved stepwise because no function is imaginable for the intermediate stages; critics answered by describing intermediate functions, which is the appropriate reply to incredulity.
  • •During the 2020-2023 debate over the origin of SARS-CoV-2, some commentators found it unbelievable that a virus could emerge naturally so close to a virology institute, while others found it unbelievable that a laboratory leak could go undetected; each side offered its incredulity as evidence while the question remained open.
  • •Voters on the losing side of a close election say “there is no way that many people voted for him” and treat their own surprise as grounds for suspecting fraud; the 2000, 2016, and 2020 U.S. presidential elections each produced this reaction.
  • •A juror announces that the defense account “does not make sense to me” and votes accordingly, although the account is corroborated by records the juror did not follow.

Ethical guidelines

  • ●Treat your own incredulity as a prompt to learn, not as a premise; say “I do not understand how that could work” and then ask.
  • ●Do not offer an audience's disbelief back to them as confirmation; if a claim is false, show the evidence against it.
  • ●When you present a counterintuitive finding, anticipate incredulity and supply the mechanism, so that listeners are not left to reason from their own imagination.
  • ●Do not pair “that cannot be right” with a ready-made alternative; the alternative must earn its own evidence.

How to defend against it

  • ►Convert the verdict back into a question: “Is the problem that it is false, or that we do not yet know how it works?” Only the first is an argument.
  • ►Ask for the counter-evidence: “What have you found that shows it is false, beyond its seeming unlikely?” Incredulity with nothing behind it is an empty set.
  • ►Point to the track record: continental drift, germ theory, and quantum mechanics were all unbelievable to informed people; unbelievability is a weak predictor of falsity.
  • ►Supply or request the mechanism at the level of detail the doubter can follow; the illusion of explanatory depth usually collapses when someone tries to explain the alternative.
  • ►Where the claim is genuinely surprising, ask for the base rate and the total evidence rather than for a single intuitive picture; surprising things happen at known rates.

References

  1. Dawkins, R. (1986). The Blind Watchmaker. Longman (UK); W. W. Norton (US)
    The coinage “argument from personal incredulity” and the Montefiore example.
  2. Walton, D. (1996). Arguments from Ignorance. Pennsylvania State University Press
    The classification of incredulity arguments as a species of argument from ignorance and the conditions under which such arguments are weak.
  3. Rozenblit, L., & Keil, F. (2002). The misunderstood limits of folk science: An illusion of explanatory depth. Cognitive Science, 26(5), 521-562
    The illusion of explanatory depth that makes unfamiliar mechanisms feel suspicious.
  4. Behe, M. J. (1996). Darwin's Black Box: The Biochemical Challenge to Evolution. Free Press
    The irreducible-complexity argument cited as the example; cited as the source of the argument, not as an authority for it.
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