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A self-refuting idea is a logical fallacy that occurs when concept A is used to deny concept B, although concept A logically depends on concept B. In short, a self-refuting idea occurs when the conclusion denies the premises. It is similar to begging the question (where you assume what you are attempting to prove), but in a stolen concept, you are assuming what you want to disprove. Many conspiracy theories are self-refuting ideas.
The fallacy is a formal fallacy.
- smuggled concept
- stolen concept fallacy (coined by Ayn Rand)
- own goal
- unforced error
- shooting oneself in the foot
- friendly fire
Self-refuting ideas are relatively common among those who don't consider the assumptions they're making or what those assumptions actually mean; the result is an argument that undermines itself. This is particularly common when the person making the claim is cherry picking, since they may not bother to check if the things they're picking even are cherries.
However, a claim of self-refutation may be based on semantics or a straw man. The common Objectivist example of the Stolen Concept is Pierre-Joseph Proudhon's statement that "property is theft;" it is argued that this is self-negating, as theft requires a concept of lawful property. This ignores the author's intended definition of the two terms – Proudhon referred to the private property of landowners and capitalists, claiming they "stole" profits from workers (he called his preferred property concept "possession"). It is important to distinguish this from ad hoc attempts to rescue a self-refuting idea by adding terms to it after the fact.
One ought to be aware of the principle of charity, to take the most reasonable interpretation of one's opponent's words. An argument may be formed as a deliberate oxymoron, as a striking way of saying something, or other metaphor, and is not to be taken literally.
And one must distinguish between a self-refuting idea and the quite useful reductio ad absurdum, where one begins with the assumptions that one is trying to refute and shows that they result in a contradiction or other unwelcome conclusion.
Canceling hypotheses occurs when someone explains away the absence of the evidence for something / consequences of something by (ad hoc) introducing a new hypothesis which cancels the effect of the first.
A literary term is for a species of irony, unintentional apophasis. Intentional apophasis is to bring up a subject with the pretense of not mentioning it, such as "I will not dwell on my opponent's atheism". Unintentional apophasis is rather to bring up a subject which is best left alone. In Shakespeare's Hamlet, the Queen says, "The lady doth protest too much, methinks," thereby herself protesting too much.
- Some axioms are self-refuting, and are held to be true in spite of this; for example, the claim "everything is subjective" would require the statement itself be objectively true and is thus self-negating; any attempt to rescue it using logic would fall prey to special pleading by demanding one arbitrary exemption to the claim. Similarly the attempt at proving the existence of God by positing that everything must have a cause, while making one special exemption (namely, God) to the need for a cause, can fall prey to this as well.
- Anti-science groups will often use scientific theories or methods which assume some of the things they're trying to refute; perpetual motion claims are often based on the idea that quantum physics can be used to defeat the laws of thermodynamics, even though these laws are actually assumptions of quantum theory.
- The concepts of divine omnipotence and omniscience present a battery of methods to defeat them; an all-powerful being should be able to do things that interfere with their own ability to apply that power, or that a being stated to be both omnipotent and omniscient would be unable to do anything but the things it had foreseen itself doing and would therefore have no real power at all.
- "I do not exist" — The speaker denies the idea that she exists, but in the very act of making the statement she presumes her existence. Interestingly, people with some forms of the Cotard delusion believe that they do not exist and thus manifest this.
- "Reality is an illusion" — The concept "illusion" is derived from the concept "reality"; that is, the concept "illusion" makes no sense, unless there is indeed "reality" with which it may be contrasted.
- "Logic is arbitrary" — How could you ever determine that something is arbitrary, except by contrasting it with that which you know to be logical?
- "Nothing is certain; there are only probabilities" — And how do you propose to express or measure probability, except by comparing it to that which is certain (probability = 1)?
The proponents of "Presuppositional Apologetics" (for example, Gordon H. Clark) accuse any arguments against the existence of God of committing the Stolen Concept Fallacy on the grounds that any arguments from logic, induction or morality allegedly presuppose the existence of God (see Transcendental argument for God on Wikipedia). This is an incorrect application of the Stolen Concept fallacy, with its question-begging starting premise (X could only be sourced in my God; X exists; therefore my God exists).
Methods of rebuttal could include showing that logic does not require God — e.g., the alleged Divine Attributes (see "Omnipotence Paradox") or the idea of Creation ex nihlio are inherently illogical; that induction does not require God — e.g., miracles undermine the natural order, hence making induction faulty if God exists; and/or that objective morality does not require God — e.g., if God is the source of morality, then morality reduces to subjective divine commands.
In all cases, speakers and listeners presuppose the validity of logic and induction by the very enterprise of engaging in argument; correct arguments then use logic and induction to discover whether postulated entity X (such as God) exists. Presuppositional Apologetics / Transcendental Argument, in negating the validity of logic and induction (until and unless the speaker's God is conceded to exist), is the side committing a Stolen Concept fallacy.
- Canceling Hypotheses (Conspiracy Theory), Bruce Thompson