Slothful induction, also known as the a priori fallacy, is the failure or refusal to see or concede the most likely inference from the evidence. The failure to infer is rarely due to sloth. It demonstrates an unwillingness to follow the evidence wherever it may lead due to stupidity, dogma, or vested interests. Usually it is a red flag that someone is not principally interested in the truth of a matter. And, because inductive arguments are at best probabilistic, someone can always hold out against the preponderance of evidence. Nevertheless, there are times when it is appropriate to resist the inference of even a good inductive argument, namely, when there are countervailing reasons that support the contrary conclusion. For example, when new evidence appears against a well-established scientific theory, it can be appropriate to retain the current theory until the evidence to the contrary is sufficiently strong. In such cases an ad hoc hypothesis may be introduced to explain how the established thesis may still be true in spite of the implications of this new inductive evidence.
From Thick Headedness
- “The second fitness-enhancing cognitive capacity is the tendency to recognize that things that are similar to each other with respect to their observed properties are likely to be similar with respect to their unobserved properties… This capacity is advantageous because the principle it is centered around is true, and failure to reason in accordance with the principle can be deadly. Failure to infer that these round, shiny, bright berries are likely to be poisonous from the fact that those other round, shiny, bright red berries produced frothing at the mouth and then death in one’s companion yesterday may well lead to trouble for oneself today.” (Wielenberg, God and the Reach of Reason, p. 90.)
- “Smith believes an open flame can ignite gasoline (he uses matches to light bonfires, etc.), and Smith believes the match he now holds has an open flame (he would not touch the tip, etc.), and Smith is not suicidal.
Yet Smith decides to see whether a gasoline tank is empty by looking inside while holding the match nearby for illumination. Similar stories often appear in newspapers; this is approximately how one of Faulkner’s
characters, Eck Snopes, dies in The Town.” (Cherniak, Minimal Rationality, p. 57.) » See the Darwin Awards for more inductive failures of this sort.
From Vested Interests
- As the scientific evidence linking lung cancer to smoking mounted in the 1950s and following, tobacco companies consistently resisted and repudiated the evidence. For example, the Brown & Williamson Tobacco Corporation stated: “It is our opinion that the repeated assertion without conclusive proof that cigarettes cause disease — however well-intentioned — constitutes a disservice to the public.” And, the Tobacco Institute of Hong Kong: “The view that smoking causes specific diseases remains an opinion or a judgment, and not an established scientific fact.” (Agin, Junk Science, p. 89.) » Here we have a clear case where economic interests prevented the admission of an overwhelmingly probable conclusion. Notice how these statements capitalize on the nature of inductive arguments, that they are at best probabilistic and never, strictly speaking, conclusive.
- “I will never accept the news of aspartame safety. I think it is a “business” decision to discredit/discount the research results that aspartame DOES cause cancer, major nerve disorders, birth defects, and brain imbalances. Think about it – can you imagine the chaos that will occur when the truth of aspartame dangers is accredited. The FDA has known about the dangers, the corporations have known about the dangers, and the medical community (if it is really worth anything) has known about the dangers.” (Dr. Janet Starr Hull at sweetpoison.com, emphasis added, cited at Science Based Medicine)
- In political campaigns, as the election nears, even when a candidate is clearly behind in all the polls, if asked, the candidate or his or her representatives will invariably deny the almost inevitable outcome. This response is understandable and pragmatic. If said candidate’s supporters lose hope, they are less likely to trouble themselves to cast their vote on election day, and the outcome will be even more lopsided and the slim chance for an upset slips even further out of reach.
Ad hoc Escapism
- “It is possible that a materialistic explanation of consciousness might be found, but that does not make the claim that consciousness is non-physical an argument from ignorance… At any given time, scientists should infer the best current explanation of the available evidence, and right now, the best evidence from both neuroscience and rigorous philosophical analysis is that consciousness is not reducible to the physical. Churchland’s refusal to draw this inference is based not on evidence, but on what Karl Popper called “promissory materialism,” a reliance on the mere speculative possibility of a materialistic explanation. Since this attitude can be maintained indefinitely, it means that even if a non-materialist account is correct (and supported by overwhelming evidence), that inconvenient truth can always be ignored. Surely the project of science should be one of following the evidence wherever it leads, not of protecting a preconceived materialist philosophy.” (Menuge, Evangelical Philosophical Society Blog, Oct, 23, 2008.)
- “Once upon a time two explorers came upon a clearing in the jungle. In the clearing were growing many flowers and many weeds. One explorer says, ‘Some gardener must tend this plot.’ The other disagrees: ‘There is no gardener.’ So they pitch their tents and set a watch. No gardener is ever seen. ‘But perhaps he is an invisible gardener,’ the Believer says. So they set up a barbed-wire fence. They electrify it. They patrol with bloodhounds. But they hear no shrieks that would suggest some intruder had received a shock. No movements of the wire ever betray an invisible climber. The bloodhounds never give a cry. Yet still the Believer is not convinced: ‘But there is a gardener, invisible, intangible, insensible to electric shocks, a gardener who comes secretly to look after the garden which he loves.’ At last the Skeptic despairs: ‘But what remains of your original assertion? Just how does what you call an invisible, intangible, eternally elusive gardener differ from an imaginary gardener or even from no gardener at all?'” (Smith, Ethical and Religious Thought in Analytic Philosophy of Language, p. 24.)
With the possible exception of Orwellian measures, it’s generally impossible to force someone to change their mind, and this is a very good thing. About all you can do is 1) revisit the evidence and point to the strength of the inference. 2) If there are additional sources of evidence that can be brought to bear, one should do so and mount a cumulative case for the conclusion. 3) To ascertain whether it is even worth arguing, ask: “If this evidence does not persuade you, what would constitute sufficient evidence to change your mind?” For example, the author at Ebon Musings takes this tack against biblical inerrantists who refuse to acknowledge apparent contradictions as real contradictions.
I accused Mr. Holding and his inerrantist ilk of being trapped in a mindset that will simply not allow the Bible to be wrong, no matter how obvious the error or inconsistency, and posed them the following question: ‘What would it take to convince you that you were wrong? What, hypothetically, would the Bible have to say to be contradictory? Can you give an imaginary example of two discrepant verses that you would accept as impossible to resolve?'”
It’s worth remembering that though someone may be unwilling to concede a point at the moment or in public, they may very well be moved by the evidence privately or in subsequent reflection. Though, to save face, people are disinclined to make an about face, they are also, as Doug Geivett puts it, “naturally truth-interested and exquisitely evidence-sensitive”.
Rhetorically, for the sake of the audience in a discussion or public debate, it can be effective to rehearse and press the point. “So just to be clear, we have seen that for these reasons there is strong evidence that this is the most likely conclusion. You refuse to concede the point but haven’t given us any good reason for not following this evidence where it leads.” This approach reminds the audience of the evidence and draws attention to an opponent’s recalcitrance toward the truth of the matter.