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2. Reason / F. Fallacies / 1. Fallacy

[distinctive types of recurrent error in human reasoning]

8 ideas
Induction assumes some uniformity in nature, or that in some respects the future is like the past [Ayer]
     Full Idea: In all inductive reasoning we make the assumption that there is a measure of uniformity in nature; or, roughly speaking, that the future will, in the appropriate respects, resemble the past.
     From: A.J. Ayer (The Problem of Knowledge [1956], 2.viii)
     A reaction: I would say that nature is 'stable'. Nature changes, so a global assumption of total uniformity is daft. Do we need some global uniformity assumptions, if the induction involved is local? I would say yes. Are all inductions conditional on this?
The Struthionic Fallacy is that of burying one's head in the sand [Quine]
     Full Idea: The Struthionic Fallacy is that of burying one's head in the sand [which I name from the Greek for 'ostrich']
     From: Willard Quine (Lecture on Nominalism [1946], §4)
     A reaction: David Armstrong said this is the the fallacy involved in a denial of universals. Quine is accusing Carnap and co. of the fallacy.
It is a fallacy to explain the obscure with the even more obscure [Hale/Wright]
     Full Idea: The fallacy of 'ad obscurum per obscurius' is to explain the obscure by appeal to what is more obscure.
     From: B Hale / C Wright (The Metaontology of Abstraction [2009], §3)
     A reaction: Not strictly a fallacy, so much as an example of inadequate explanation, along with circularity and infinite regresses.
'Reification' occurs if we mistake a concept for a thing [Schaffer,J]
     Full Idea: 'Reification' occurs when a mere concept is mistaken for a thing. We seem generally prone to this sort of error.
     From: Jonathan Schaffer (Causation and Laws of Nature [2008], 3.1)
     A reaction: Personally I think we should face up to the fact that this is the only way we can think about generalised or abstract entities, and stop thinking of it as an 'error'. We have evolved to think well about objects, so we translate everything that way.
'Affirming the consequent' fallacy: φ→ψ, ψ, so φ [Hanna]
     Full Idea: The fallacy of 'affirming the consequent' is of the form φ→ψ, ψ, so φ.
     From: Robert Hanna (Rationality and Logic [2006], 5.4)
'Denying the antecedent' fallacy: φ→ψ, ¬φ, so ¬ψ [Hanna]
     Full Idea: The fallacy of 'denying the antecedent' is of the form φ→ψ, ¬φ, so ¬ψ.
     From: Robert Hanna (Rationality and Logic [2006], 5.4)
We can list at least fourteen informal fallacies [Hanna]
     Full Idea: Informal fallacies: appeals to force, circumstantial factors, ignorance, pity, popular consensus, authority, generalisation, confused causes, begging the question, complex questions, irrelevance, equivocation, black-and-white, slippery slope etc.
     From: Robert Hanna (Rationality and Logic [2006], 7.3)
Fallacies are errors in reasoning, 'formal' if a clear rule is breached, and 'informal' if more general [PG]
     Full Idea: Fallacies are errors in reasoning, labelled as 'formal' if a clear rule has been breached, and 'informal' if some less precise error has been made.
     From: PG (Db (ideas) [2031])
     A reaction: Presumably there can be a grey area between the two.