Ad hominem, short for argumentum ad hominem, refers to several types of arguments that are fallacious. Often nowadays this term refers to a rhetorical strategy where the speaker attacks the character, motive, or some other attribute of the person making an argument rather than attacking the substance of the argument itself. This avoids genuine debate by creating a personal attack as a diversion often using a totally irrelevant, but often highly charged attribute of the opponent's character or background. The most common form of this fallacy is "A" makes a claim of "fact," to which "B" asserts that "A" has a personal trait, quality or physical attribute that is repugnant thereby going entirely off-topic, and hence "B" concludes that "A" has their "fact" wrong - without ever addressing the point of the debate. Many contemporary politicians routinely use ad hominem attacks, which can be encapsulated to a derogatory nickname for a political opponent.
Ethical non-naturalism is the meta-ethical view which claims that:
- Ethical sentences express propositions.
- Some such propositions are true.
- Those propositions are made true by objective features of the world, independent of human opinion.
- These moral features of the world are not reducible to any set of non-moral features.
Fallacies of definition are the various ways in which definitions can fail to explain terms. The phrase is used to suggest an analogy with an informal fallacy. Definitions may fail to have merit, because they are overly broad, overly narrow, or incomprehensible; or they use obscure or ambiguous language, contain mutually exclusive parts, or are circular.
A loaded question is a form of complex question that contains a controversial assumption.
No true Scotsman or appeal to purity is an informal fallacy in which one attempts to protect an a posteriori claim from a falsifying counterexample by covertly modifying the initial claim. Rather than admitting error or providing evidence that would disqualify the falsifying counterexample, the claim is modified into an a priori claim in order to definitionally exclude the undesirable counterexample. The modification is signalled by the use of non-substantive rhetoric such as "true", "pure", "genuine", "authentic", "real", etc.
In a slippery slope argument, a course of action is rejected because the slippery slope advocate believes it will lead to a chain reaction resulting in an undesirable end or ends. The core of the slippery slope argument is that a specific decision under debate is likely to result in unintended consequences. The strength of such an argument depends on whether the small step really is likely to lead to the effect. This is quantified in terms of what is known as the warrant.
In philosophical ethics, the naturalistic fallacy is the claim that it is possible to define good in terms of natural entities, or properties such as pleasant or desirable. The term was introduced by British philosopher G. E. Moore in his 1903 book Principia Ethica.
In classical rhetoric and logic, begging the question or assuming the conclusion is an informal fallacy that occurs when an argument's premises assume the truth of the conclusion. Historically, begging the question refers to a fault in a dialectical argument in which the speaker assumes some premise that has not been demonstrated to be true. In modern usage, it has come to refer to an argument in which the premises assume the conclusion without supporting it. This makes it an example of circular reasoning.
Formal, formality, informal or informality imply the complying with, or not complying with, some set of requirements. They may refer to:
Poisoning the well is a type of informal fallacy where adverse information about a target is preemptively presented to an audience, with the intention of discrediting or ridiculing something that the target person is about to say. Poisoning the well can be a special case of argumentum ad hominem, and the term was first used with this sense by John Henry Newman in his work Apologia Pro Vita Sua (1864).
The fallacy of suppressed correlative is a type of argument that tries to redefine a correlative so that one alternative encompasses the other, i.e. making one alternative impossible. This has also been known as the fallacy of lost contrast and the fallacy of the suppressed relative.
A persuasive definition is a form of stipulative definition which purports to describe the true or commonly accepted meaning of a term, while in reality stipulating an uncommon or altered use, usually to support an argument for some view, or to create or alter rights, duties or crimes. The terms thus defined will often involve emotionally charged but imprecise notions, such as "freedom", "terrorism", "democracy", etc. In argumentation the use of a persuasive definition is sometimes called definist fallacy.
An etymological fallacy is an argument of equivocation, arguing that a word is defined by its etymology, and that its customary usage is therefore incorrect.
The moralistic fallacy is the informal fallacy of assuming that an aspect of nature which has socially unpleasant consequences cannot exist. Its typical form is "if X were true, then Z would happen! Thus, X is false", where Z is a morally, socially or politically undesirable thing. What should be moral is assumed a priori to also be naturally occurring. The moralistic fallacy is sometimes presented as the inverse of the naturalistic fallacy. However, it could be seen as a variation of the very same naturalistic fallacy; the difference between them could be considered pragmatical, depending on the intentions of the person who uses it: naturalistic fallacy if the user wants to justify existing social practices with the argument that they are natural; moralistic fallacy if the user wants to combat existing social practices with the argument of denying that they are natural.
In logic and philosophy, a formal fallacy, deductive fallacy, logical fallacy or non sequitur is a pattern of reasoning rendered invalid by a flaw in its logical structure that can neatly be expressed in a standard logic system, for example propositional logic. It is defined as a deductive argument that is invalid. The argument itself could have true premises, but still have a false conclusion. Thus, a formal fallacy is a fallacy in which deduction goes wrong, and is no longer a logical process. This may not affect the truth of the conclusion, since validity and truth are separate in formal logic.
Acatalepsy, in philosophy, is incomprehensibleness, or the impossibility of comprehending or conceiving some or all things. The doctrine held by the ancient Skeptic philosophers, that human knowledge never amounts to certainty, but only to probability.
The definist fallacy is a logical fallacy, identified by William Frankena in 1939, that involves the definition of one property in terms of another.
In argumentation theory, an argumentum ad populum is a fallacious argument which is based on claiming a truth or affirming something is good because many people think so.
