Fallacies of contraversion must involve either those of obversion or conversion since the process is a combination of the two.
(6) Fallacies in language, because they result from permitting more than one interpretation, may be also denominated fallacies of equivocation.
(1) Ambiguous middle is the fallacy of giving to the middle term a double meaning.
The fallacy of four terms, as the name signifies, exists when the argument has four terms in both form and meaning. Ambiguous middle is a matter of four terms in meaning but only three in form.
(2) The fallacy of amphibology is committed when the given proposition conveys more than one meaning. In order to maintain their prestige the ancient oracles made use of this fallacy.
(3) The fallacy of accent springs from placing undue emphasis on some word or group of words. Newspaper and demagogues are prone to this error, that they may thus create an unfavorable impression towards those whom they oppose.
(4) The fallacy of composition is committed when it is assumed that what is true _distributively_ is likewise true _collectively_. “All” meaning _each one_ and “all” meaning the _whole class_ often leads to the fallacy of composition.
(5) The fallacy of division is committed when it is assumed that what is true _collectively_ is true _distributively_.
(6) The fallacy of figure of speech is occasioned by assuming that words of the same root have the same meaning.
(7) Fallacies in thought are likewise called fallacies of assumption, because of the tendency to assume as true something which demands further proof.
(1) The fallacy of accident occurs when one reasons from a general truth to an accident case. It is the favored fallacy of the doctrinaire, the reformer and the vender of “cure-alls.”
(2) The fallacy of converse accident occurs when one reasons from an accidental case to a general truth.
Both accident and converse accident are made possible because rules, definitions, maxims, etc., have _exceptions_. It is easy to confuse division and composition with the fallacies of accident. Division and composition are concerned with the _collective and distributive use of terms_, whereas the fallacies of accident involve the use of notions in a _general and accidental sense_. The former represent notions which may be _counted or enumerated_ while the latter concern notions which are _logical_ rather than numerical. Composition and division involve “number of,” accident, “meaning of.”