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Logic and rhetoric
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.
- "I do not exist" — The speaker denies the idea that they exist, but in the very act of making the statement they presumes their existence. Interestingly, people with some forms of the Cotard delusion believe that they do not exist and thus manifest this.
- "Reality is a(n) illusion/simulation/hallucination" — The concepts "illusion", "simulation" and "hallucination" are derived from the concept "reality"; that is, they can make no sense, unless there is indeed "reality" with which either may be contrasted.
- "Logic is arbitrary/illogical" — How could you ever determine that something is arbitrary or illogical, except by contrasting it with that which you know to be logical?
Statements or concepts involving explicit or implicit absolutes/universals
Although statements and concepts involving them explicitly and implicitly which are not self-refuting ideas do indeed exist, absolutes and universals generally create these readily due to their nature of allowing no exception to be given and thus requiring an escape hatch to get out of any apparent exception.
- 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, if not foreseen itself doing, at least known it was able to do and would therefore have no real power at all; not to mention that it should still be able to believe contradictions and if omnicredence were added to these, it should have to actually believe them. Also, the other quadruplets, divine omnipresence and omnibenevolence will defeat them (and also the hypothetical additional divine omnicredence) in their own battery of ways; an all-powerful being should be able to believe such assertions as that it actually neither likes anybody nor anything nor even exists, or an all-believing being should have to believe that it is actually able to believe such assertions as that it actually neither likes anybody nor anything nor even exists, and actually believe them, in spite of actually being present to anything at all and bearing goodwill to anything or anyone at all, and therefore knowing that it actually is present to anything at all and bears goodwill to anything or anyone at all, being omnipresent and omnibenevolent.
- "Whether or not any form of actually valid/strong argument exists, no valid/strong argument can really be sound/cogent" — The speaker may not be calling logic out as "arbitrary" or "illogical" explicitly but nevertheless denies the real possibility of any logical deduction or induction at all. But how could any arbitrary or illogical "deduction" or "induction" even be possible to determine without contrasting it with what deduction or induction is known to be logical?
- "Whether or not I exist, no one else really does or did" — If the speaker exists, the speaker presumably must have been born, but for birth to really happen someone else must really exist. In other words, this statement means "I do not exist, but if I did, I must not", which is a contradiction.
- "There is not really anything" — The speaker may not be invoking the concept "illusion", "simulation" or "hallucination" explicitly but nevertheless denies the real existence of anything at all. But the very act of speaking presupposes the real existence of an entity which is able to speak and a language containing at least only the relatively well-defined words being said.
- "There is no sign that is really well-enough defined to be used" — The very use of any given sign generally presupposes that it is indeed well-enough defined to be used.
- "Whether or not anything exists, nothing can be known about anything that exists" — If nothing else, it has to be possible to know that anything that exists, exists.
- "Whether or not anything can be known about anything that exists, nothing that is known about anything that exists can be communicated to others" — Then is language not really for anything?
- "Everything is a(n) illusion/simulation/hallucination; nothing actually exists," — Even an illusion, simulation or hallucination still exists, if only apparently. But the concept apparently exists can make no sense unless there is indeed something that "actually exists" with which anything else may be contrasted.
- "Nothing is certain or impossible; there are only probabilities" — And how do you propose to express or measure probability, except by comparing it either to that which is certain (probability = 1) or to that which is impossible (probability = 0)?
- Necessitarian determinism is sometimes claimed to be entailed by the Principle of Sufficient Reason, even though contingency is actually an "assumption" of this principle.
The proponents of either descriptive or normative egoism (for example of the latter, objectivism) propose that they ultimately do what they do in their own self-interest, whether over a short or a long term; or that it is necessary and sufficient for what they do to be morally right or rational if it is ultimately in their own self-interest, whether over a short or a long term. On this score, objectivists are notorious for claiming the point that only what they do that is ultimately in their own self-interest, specifically over a short term, is really morally right. This means, for example, that the mere existence of children is technically morally wrong, a prescription which would extinguish humanity if followed. But this is no reverse special plea that only objectivism is really prey to self-refutation because it self-refutes so egregiously. In fact, even descriptive (or psychological) egoism really only defines altruism away without saying that it doesn't really exist.
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