Dcleve wrote the following as an aside in a question about indirect realism:

Our WANTING certainty – is irrelevant. Worse, it is an explicit fallacy!

I liked that question and up-voted it, but I am puzzled why wanting certainty is a fallacy. It did not seem relevant to the original question to bring it up there, so I am asking it here.

Specifically, what I am looking for is

  1. the name of the fallacy,
  2. a reference to a description of it where I can get more information, and
  3. whether the fallacy passes Bo Bennett's demarcation test showing it is not a pseudo-logical fallacy.

Here is Bennett's test:

  1. It must be an error in reasoning, not a factual error.
  2. It must be commonly applied to an argument either in the form of the argument or the interpretation of the argument.
  3. It must be deceptive in that it often fools the average adult.


Bo Bennett, "Pseudo-Logically Fallacies", Logically Fallacious https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/6/Pseudo-Logical-Fallacies

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    Wanting is not an argument. How can it be a fallacy? – Eliran Dec 6 '18 at 15:14
  • @Eliran There may be a way to phrase this as an argument. I am keeping an open mind about what answers might appear. – Frank Hubeny Dec 6 '18 at 15:22
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    I do not think it is a recognized named fallacy. What I think it refers to is applying a misplaced standard of certainty. Demanding, say, mathematical certainty for empirical knowledge would lead to the conclusion that there is no empirical knowledge (and to no convictions in criminal trials). Since this form of argument is not uncommon (crude postmodernism comes to mind) I suppose it can be called a fallacy. Criticism of overreaching standards is common in the argumentation theory, e.g. Toulmin's. – Conifold Dec 6 '18 at 19:22
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    Wanting is a mental state, a feeling. So for the mind to want material certainty within a constantly changing system of physical flux is delusional, or at least very frustrating. wikidiff.com/delusion/fallacy However, it may just be that the mind is only trying to justify itself with entropic matter. The mind is attempting to retain its sanity. Because, when too closely attached to or psychologically bound with matter, the mind feels intense discomfort being aware of its rapid decline toward death. – Bread Dec 7 '18 at 6:50
  • I interpreted this from a Bayesian perspective: All belief is continuously updated as evidence is acquired, in a process that breaks down if anything is ever assigned a 100% or 0% likelihood. Once something is 100% believed ('certain'), it is more likely that you'll reject all further evidence than revise your belief. – kbelder Dec 10 '18 at 18:41

The fallacy is to treat the satisfaction, or failure to satisfy, of a desire for certainty, as support for or against a POV. The fallacy is that of wishful thinking. It is discussed in a prior PSE entry: Does the fallacy in "it's true because I would like it to be true" have a name?


In your question, “wanting certainty” has no context. There are no hypotheses, therefore this is not an argument. So no fallacy is made. A person wanting certainty is merely a matter of fact.

Based on the reference, which gives this more context, I will rephrase it into what I believe to be the implied argument.

A belief system does not allow one to know anything (of which the belief system claims) to be true or false, therefore it’s claims are false.

This claims that, by the contrapositive, for a belief system to be true, it must allow one to know something to be true or false. A parallel statement would be “if something is true, then it can be known.”

Another interpretation is: A belief system does not allow one to know anything to be true or false, therefore it is not useful.

In this interpretation, I see no fallacy.

  • +1 Your paraphrasing helps clarify the issue. – Frank Hubeny Dec 6 '18 at 16:00

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