A self-refuting idea or self-defeating idea is an idea or statement whose falsehood is a
logical consequence
Logical consequence (also entailment or logical implication) is a fundamental concept in logic which describes the relationship between statement (logic), statements that hold true when one statement logically ''follows from'' one or more stat ...
of the act or situation of holding them to be true. Many ideas are called self-refuting by their detractors, and such accusations are therefore almost always controversial, with defenders stating that the idea is being misunderstood or that the
argument
An argument is a series of sentences, statements, or propositions some of which are called premises and one is the conclusion. The purpose of an argument is to give reasons for one's conclusion via justification, explanation, and/or persu ...
is invalid. For these reasons, none of the ideas below are unambiguously or incontrovertibly self-refuting. These ideas are often used as
axioms, which are definitions taken to be true (
tautological assumptions), and cannot be used to test themselves, for doing so would lead to only two consequences:
consistency
In deductive logic, a consistent theory is one that does not lead to a logical contradiction. A theory T is consistent if there is no formula \varphi such that both \varphi and its negation \lnot\varphi are elements of the set of consequences ...
(
circular reasoning
Circular reasoning (, "circle in proving"; also known as circular logic) is a fallacy, logical fallacy in which the reasoner begins with what they are trying to end with. Circular reasoning is not a formal logical fallacy, but a pragmatic defect ...
) or exception (self-
contradiction).
Variations
Directly self-denying statements
Directly self-denying statements are characterised by being necessarily (or inherently) false. The
Epimenides paradox is a statement of the form "this statement is false". Such statements troubled philosophers, especially when there was a serious attempt to formalize the foundations of logic.
Bertrand Russell
Bertrand Arthur William Russell, 3rd Earl Russell, (18 May 1872 – 2 February 1970) was a British philosopher, logician, mathematician, and public intellectual. He had influence on mathematics, logic, set theory, and various areas of analytic ...
developed his "
Theory of Types" to formalize a set of rules that would prevent such statements (more formally
Russell's paradox) being made in symbolic logic. This work has led to the modern formulation of
axiomatic set theory. While Russell's formalization did not contain such paradoxes,
Kurt Gödel showed that it must contain
independent statements. Any
logical system that is rich enough to contain elementary arithmetic contains at least one proposition whose interpretation is ''this proposition is unprovable'' (from within the logical system concerned), and hence no such system can be both
complete and
consistent
In deductive logic, a consistent theory is one that does not lead to a logical contradiction. A theory T is consistent if there is no formula \varphi such that both \varphi and its negation \lnot\varphi are elements of the set of consequences ...
.
Indirectly self-denying statements
One form of an indirect self-denying statement is the "Stolen Concept": the act of using a concept while ignoring, contradicting or denying the validity of the concepts on which it logically and/or genetically depends. The idea of the "Stolen Concept" is generally attributed to be first noted by
Ayn Rand and then later supported by followers of
Objectivism. Much like Objectivism the idea of the "Stolen Concept" does not have mainstream acceptance in academia. An example of the stolen concept fallacy is anarchist
Pierre-Joseph Proudhon's statement,
"All property is theft".
Others have said the statement is fallacious only on a superficial reading of Proudhon, devoid of context. Proudhon used the term "property" with reference to claimed ownership in land, factories, etc. He believed such claims were illegitimate, and thus a form of theft from the commons. Proudhon explicitly states that the phrase "property is theft" is analogous to the phrase "slavery is murder". According to Proudhon, the slave, though biologically alive, is clearly in a sense "murdered". The "theft" in his terminology does not refer to ownership any more than the "murder" refers directly to physiological death, but rather both are meant as terms to represent a denial of specific rights.
In logic
Self-refutation plays an important role in some inconsistency tolerant logics (e.g.
paraconsistent logics and direct logic) that lack
proof by contradiction
In logic, proof by contradiction is a form of proof that establishes the truth or the validity of a proposition by showing that assuming the proposition to be false leads to a contradiction.
Although it is quite freely used in mathematical pr ...
. For example, the negation of a proposition can be proved by showing that the proposition implies its own negation. Likewise, it can be inferred that a proposition cannot be proved by (1) showing that a proof would imply the negation of the proposition or by (2) showing a proof would imply that the negation of the proposition can be proved.
Examples
Brain in a vat
Brain in a vat is a
thought experiment
A thought experiment is an imaginary scenario that is meant to elucidate or test an argument or theory. It is often an experiment that would be hard, impossible, or unethical to actually perform. It can also be an abstract hypothetical that is ...
in philosophy which is premised upon the
skeptical hypothesis that one could actually be a brain in a vat receiving electrical input identical to that which would be coming from the nervous system. Similar premises are found in
Descartes's
evil demon and
dream argument.
Philosopher
Hilary Putnam
Hilary Whitehall Putnam (; July 31, 1926 – March 13, 2016) was an American philosopher, mathematician, computer scientist, and figure in analytic philosophy in the second half of the 20th century. He contributed to the studies of philosophy of ...
argues that some versions of the thought experiment would be inconsistent due to
semantic externalism. For a brain in a vat that had only ever experienced the simulated world, the statement "I'm not a brain in a vat" is true. The only possible brains and vats it could be referring to are simulated, and it is true that it is not a simulated brain in a simulated vat. By the same argument, saying "I'm a brain in a vat" would be false.
Determinism
It has been argued by advocates of
libertarian free will that to call
determinism
Determinism is the Metaphysics, metaphysical view that all events within the universe (or multiverse) can occur only in one possible way. Deterministic theories throughout the history of philosophy have developed from diverse and sometimes ov ...
a rational statement is doubly self-defeating.
#To count as rational, a belief must be ''freely'' chosen, which according to the determinist is impossible
#Any kind of debate seems to be posited on the idea that the parties involved are trying to change each other's minds.
Ethical egoism
It has been argued that extreme
ethical egoism is self-defeating. Faced with a situation of limited resources, egoists would consume as much of the resource as they could, making the overall situation worse for everybody. Egoists may respond that if the situation becomes worse for everybody, the egoist will also be negatively placed, such that it is not, in fact, in the egoist's rational self-interest to take things to such extremes. However, the (unregulated)
tragedy of the commons and the (one-off)
prisoner's dilemma are cases in which, on the one hand, it is rational for an individual to seek to take as much as possible ''even though'' to do so makes things worse for everybody,, and on the other hand, the behaviour remains rational ''even though'' it is ultimately self-defeating. That is to say, in these cases ''self-defeating'' does not imply ''self-refuting''. Egoists might respond that a tragedy of the commons assumes some degree of
public land; that is, a commons forbidding
homesteading
Homesteading is a lifestyle of self-sufficiency. It is characterized by subsistence agriculture, home preservation of food, and may also involve the small scale production of textiles, clothing, and craft work for household use or sale. H ...
requires regulation. Thus, an argument against the tragedy of the commons, in this belief system, is fundamentally an argument for
private property rights and the system that recognizes both property rights and
rational self-interest: capitalism.
More generally, egoists might say that an increasing respect for
individual rights uniquely allows for increasing
wealth creation and increasing usable resources despite a fixed amount of
raw materials (e.g., the West pre-1776 versus post-1776, East Germany versus West Germany, Hong Kong versus mainland China, North Korea versus South Korea, etc.).
Eliminative materialism
The philosopher
Mary Midgley states that the idea that ''nothing exists except matter'' is also self-refuting because if it were true neither it, nor any other idea, would exist, and similarly that an argument to that effect would be self-refuting because it would deny its own existence. Several other philosophers also argue that
eliminative materialism is self-refuting.
However, other forms of
materialism
Materialism is a form of monism, philosophical monism according to which matter is the fundamental Substance theory, substance in nature, and all things, including mind, mental states and consciousness, are results of material interactions. Acco ...
may escape this kind of argument because, rather than eliminating the
mental, they seek to
identify it with, or
reduce it to, the material. For instance,
identity theorists such as
J. J. C. Smart,
Ullin Place and
E. G. Boring state that ideas exist materially as patterns of
neural structure and activity. Christian apologist
J.P. Moreland states that such arguments are based on semantics.
Evolutionary naturalism
Alvin Plantinga
Alvin Carl Plantinga (born November 15, 1932) is an American analytic philosophy, analytic philosopher who works primarily in the fields of philosophy of religion, epistemology (particularly on issues involving theory of justification, epistemic ...
argues in his
evolutionary argument against naturalism that the combination of naturalism and evolution is "in a certain interesting way self-defeating" because if it were true there would be insufficient grounds to believe that human cognitive faculties are reliable. Consequently, if human cognitive abilities are unreliable, then any human construct, which by implication utilizes cognitive faculties, such as evolutionary theory, would be undermined. In this particular case, it is the confluence of evolutionary theory and naturalism that, according to the argument, undermine the reason for believing themselves to be true. Since Plantinga originally formulated the argument, a few theistic philosophers and Christian apologists have agreed. There has also been a considerable backlash of papers arguing that the argument is flawed in a number of ways, one of the more recent ones published in 2011 by Feng Ye (see also the references in the ''
Evolutionary argument against naturalism'' article).
Foundationalism
The philosopher
Anthony Kenny argues that the idea, "common to theists like
Aquinas
Thomas Aquinas ( ; ; – 7 March 1274) was an Italian Dominican Order, Dominican friar and Catholic priest, priest, the foremost Scholasticism, Scholastic thinker, as well as one of the most influential philosophers and theologians in the W ...
and
Descartes and to an atheist like
Russell" that "Rational belief
seither self-evident or based directly or indirectly on what is evident" (which he termed "foundationalism" following
Plantinga) is self-refuting on the basis that this idea is itself neither self-evident nor based directly or indirectly on what is evident and that the same applies to other formulations of such foundationalism. However, the
self-evident impossibility of
infinite regress can be offered as a justification for foundationalism. Following the identification of problems with "naive foundationalism", the term is now often used to focus on
incorrigible beliefs (modern foundationalism), or
basic beliefs (
reformed foundationalism).
Philosophical skepticism
Philosophical skeptics state that "nothing can be known". This has caused some to ask if nothing can be known then can that statement itself be known, or is it self-refuting. One very old response to this problem is
academic skepticism
Academic skepticism refers to the philosophical skepticism, skeptical period of the Platonic Academy, Academy dating from around 266 BCE, when Arcesilaus became scholarch, until around 90 BCE, when Antiochus of Ascalon rejected skepticism, altho ...
: an exception is made for the skeptic's own statement. This leads to further debate about consistency and
special pleading.
Relativism
It is often stated that
relativism about
truth
Truth or verity is the Property (philosophy), property of being in accord with fact or reality.Merriam-Webster's Online Dictionarytruth, 2005 In everyday language, it is typically ascribed to things that aim to represent reality or otherwise cor ...
must be applied to itself. The cruder form of the argument concludes that since the relativist is calling relativism an absolute truth, it leads to a
contradiction. Relativists often rejoin that in fact relativism is only relatively true, leading to a subtler problem: the absolutist, the relativist's opponent, is perfectly entitled, by the relativist's ''own'' standards, to reject relativism. That is, the relativist's arguments can have no
normative force over someone who has different
basic beliefs.
Verification and falsification principles
The statements "statements are meaningless unless they can be empirically verified" and "statements are meaningless unless they can be empirically falsified" have both been called self-refuting on the basis that they can neither be empirically verified nor falsified. Similar arguments have been made for statements such as "no statements are true unless they can be shown empirically to be true", which was a problem for
logical positivism.
[See e.g. Keith Ward, '' Is Religion Dangerous?'' p. 86.]
Moderation In All Things
The perhaps ancient, proverbial saying "all things in moderation" is itself a call to excess in that it commands moderation in every single possible thing. An actually moderate assertion would be something like "most things in moderation" or more precisely, "a moderate number of things in moderation." However, many philosophers use the saying in the context of ethics.
See also
*
Antinomy
* ''
Peritrope''
*
Paradox
*
Performative contradiction
*
Self-defeating prophecy
References
{{DEFAULTSORT:Self-Refuting Idea
Logic