====== Illicit process ======

Describes an (invalid) [[glossary:syllogism|syllogism]], in which either the //major// or //minor// term is not used according to the rules of [[glossary:distributivity|distributivity]].

Example of a syllogism<span noprint> [[app>#AA4A|Show in Syllogism-Finder App]]</span> with an //undistributed minor term//:

> All <var>dogs</var> are <var>mamals</var>.
> All <var>mamals</var> are <u questionable "Undistributed minor term"><var>animals</var></u>.
> <span conclusio><s invalid">Therefore, all <var><u questionable "Distributed position">animals</u></var> are <var>dogs</var>.</s></span>

All three statements here are of type **A** ("All <abbr "Subject">S</abbr> are <abbr "Predicate">P</abbr>"), in which the //subject// ("<abbr "Subject">S</abbr>") is in a //distributed// and the //predicate// ("<abbr "Predicate">P</abbr>") in an undistributed position. For a syllogism to be valid, any term that is in a //distributed// position in the conclusion would also need to be distributed in the premise. As this is not the case with the minor term ("animals"), this syllogism is formally invalid.

===== Other names =====

  * Undistributed major / minor [term]
  * Illicit [process of the] major / minor [term]

<aside info>
**Note:** in some publications, this is listed as two separate fallacies, depending on whether the //major// or the //minor// term is concerned. For simplicity, those are combined here under a more general name.
</aside>

===== Rules of distributivity =====

The distribution rules for syllogisms are summarized in the article on [[glossary:distributivity|distributivity]]. The specific rule that is violated by this fallacy can be formulated as follows:

<div info>
**Remember:** If a term appears in the //conclusion// statement in a //distributed// position, it must also be //distributed// in the //premise// in which it appears.
</div>

The following table gives an overview of the distributivity of the terms in the four [[glossary:categorical_statement|categorical statement types]]:

^  <span noprint>Type</span>  ^ Statement ^ Subject ^ Predicate ^
^  A  | <q>All <abbr "Subject">S</abbr> are <abbr "Predicate">P</abbr></q> | distributed | not distributed | 
^  E  | <q>No <abbr "Subject">S</abbr> is <abbr "Predicate">P</abbr></q> | distributed | distributed | 
^  I  | <q>Some <abbr "Subject">S</abbr> are <abbr "Predicate">P</abbr></q> | not distributed | not distributed | 
^  O  | <q>Some <abbr "Subject">S</abbr> are not <abbr "Predicate">P</abbr></q> | not distributed | distributed |

In regard to the example above, the premises therein are all of the type **A**; While the //minor term// ("animals") appears in the conclusion in a //distributed// position, it is //undistributed// in the minor statement. Therefore, this form of a syllogism is //not valid//. 

===== See also =====

  * [[glossary:distributivity|Distributivity]]
  * [[logic:formal_fallacies:fallacies_of_distribution:undistributed_middle|Undistributed middle]]

===== More information =====

  * [[wp>Illicit major]] and [[wp>Illicit minor]] on //Wikipedia//
  * [[https://rationalwiki.org/wiki/Illicit_process|Illicit process]] on //RationalWiki//
  * [[http://www.fallacyfiles.org/illicitp.html|Illicit Process]] on //Fallacy Files//
  * [[https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/109/Illicit-Major|Illicit major]] and [[https://www.logicallyfallacious.com/tools/lp/Bo/LogicalFallacies/110/Illicit-Minor|Illicit Minor]] on //Logically Fallacious//