An irrelevant conclusion, also known as ignoratio elenchi or missing the point, is the informal fallacy of presenting an argument that may or may not be logically valid and sound, but fails to address the issue in question. It falls into the broad class of relevance fallacies.
In philosophical ethics, the naturalistic fallacy is the mistake of explaining something as being good reductively, in terms of natural 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, instead of supporting it.
A fallacy is the use of invalid or otherwise faulty reasoning, or "wrong moves," in the construction of an argument, which may appear stronger than it really is if the fallacy is not spotted. The term was in the Western intellectual tradition introduced in the Aristotelian De Sophisticis Elenchis.
Circular reasoning is a 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 in an argument whereby the premises are just as much in need of proof or evidence as the conclusion, and as a consequence the argument fails to persuade. Other ways to express this are that there is no reason to accept the premises unless one already believes the conclusion, or that the premises provide no independent ground or evidence for the conclusion. Begging the question is closely related to circular reasoning, and in modern usage the two generally refer to the same thing.
An enthymeme is a form of rational appeal, or deductive argument. It is also known as a rhetorical syllogism and is used in oratorical practice. While the syllogism is used in dialectic, or the art of logical discussion, the enthymeme is used in rhetoric, or the art of public speaking. Enthymemes are usually developed from premises that accord with the audience's view of the world and what is taken to be common sense. However, where the general premise of a syllogism is supposed to be true, making the subsequent deduction necessary, the general premise of an enthymeme is merely probable, which leads only to a tentative conclusion. Originally theorized by Aristotle, there are four types of enthymeme, at least two of which are described in Aristotle's work.
Henry Coppée was an American educator and author.
Reductio ad Hitlerum, also known as playing the Nazi card, is an attempt to invalidate someone else's position on the basis that the same view was held by Adolf Hitler or the Nazi Party. Arguments can correctly be called reductio ad Hitlerum if they are fallacious. Contrarily, straightforward arguments critiquing fascist components of Nazism like eugenics are not part of the association fallacy.
Informal fallacies are a type of incorrect argument in natural language. The source of the error is not just due to the form of the argument, as is the case for formal fallacies, but can also be due to their content and context. Fallacies, despite being incorrect, usually appear to be correct and thereby can seduce people into accepting and using them. These misleading appearances are often connected to various aspects of natural language, such as ambiguous or vague expressions, or the assumption of implicit premises instead of making them explicit.
Gaunilo or Gaunillon was a Benedictine monk of Marmoutier Abbey in Tours, France. He is best known for his contemporary criticism of the ontological argument for the existence of God which appeared in St Anselm's Proslogion. In his work In Behalf of the Fool, Gaunilo contends that St Anselm's ontological argument fails because logic of the same kind would force one to conclude many things exist which certainly do not. An empiricist, Gaunilo thought that the human intellect is only able to comprehend information provided by the senses.
Evolutionary ethics is a field of inquiry that explores how evolutionary theory might bear on our understanding of ethics or morality. The range of issues investigated by evolutionary ethics is quite broad. Supporters of evolutionary ethics have claimed that it has important implications in the fields of descriptive ethics, normative ethics, and metaethics.
An appeal to nature is an argument or rhetorical tactic in which it is proposed that "a thing is good because it is 'natural', or bad because it is 'unnatural'". It is generally considered to be a bad argument because the implicit (unstated) primary premise "What is natural is good" is typically irrelevant, having no cogent meaning in practice, or is an opinion instead of a fact.
Appeal to the stone, also known as argumentum ad lapidem, is a logical fallacy that dismisses an argument as untrue or absurd. The dismissal is made by stating or reiterating that the argument is absurd, without providing further argumentation. This theory is closely tied to proof by assertion due to the lack of evidence behind the statement and its attempt to persuade without providing any evidence.
Informal logic encompasses the principles of logic and logical thought outside of a formal setting. However, the precise definition of "informal logic" is a matter of some dispute. Ralph H. Johnson and J. Anthony Blair define informal logic as "a branch of logic whose task is to develop non-formal standards, criteria, procedures for the analysis, interpretation, evaluation, criticism and construction of argumentation." This definition reflects what had been implicit in their practice and what others were doing in their informal logic texts.
Henry Johnstone Jr. (1920–2000) was an American philosopher and rhetorician known especially for his notion of the "rhetorical wedge" and his re-evaluation of the ad hominem fallacy. He was Professor of Philosophy at Pennsylvania State University (1952–1984) and began studying Classics in the late 1970s. He was the founder and longtime editor of the journal Philosophy and Rhetoric and edited the Journal of Speculative Philosophy.
In logic, reductio ad absurdum, also known as argumentum ad absurdum or apagogical arguments, is the form of argument that attempts to establish a claim by showing that the opposite scenario would lead to absurdity or contradiction. This argument form traces back to Ancient Greek philosophy and has been used throughout history in both formal mathematical and philosophical reasoning, as well as in debate.
An ontological argument is a philosophical argument, made from an ontological basis, that is advanced in support of the existence of God. Such arguments tend to refer to the state of being or existing. More specifically, ontological arguments are commonly conceived a priori in regard to the organization of the universe, whereby, if such organizational structure is true, God must exist.
In argumentation theory, an argumentum ad populum is a fallacious argument which is based on claiming a truth or affirming something is good because the majority thinks so.
In argumentation theory, an argumentation scheme or argument scheme is a template that represents a common type of argument used in ordinary conversation. Many different argumentation schemes have been identified. Each one has a name and presents a type of connection between premises and a conclusion in an argument, and this connection is expressed as a rule of inference. Argumentation schemes can include inferences based on different types of reasoning—deductive, inductive, abductive, probabilistic, etc.
