Editing Syllogism (section)

==Syllogistic fallacies==
People often make mistakes when reasoning syllogistically.<ref>See, e.g., Evans, J. St. B. T (1989). ''Bias in human reasoning''. London: LEA.</ref>

For instance, from the premises some A are B, some B are C, people tend to come to a definitive conclusion that therefore some A are C.<ref>Khemlani, S., and P. N. Johnson-Laird. 2012. "Theories of the syllogism: A meta-analysis." ''[[Psychological Bulletin]]'' 138:427–57.</ref><ref>Chater, N., and M. Oaksford. 1999. "The Probability Heuristics Model of Syllogistic Reasoning." ''[[Cognitive Psychology (journal)|Cognitive Psychology]]'' 38:191–258.</ref> However, this does not follow according to the rules of classical logic. For instance, while some cats (A) are black things (B), and some black things (B) are televisions (C), it does not follow from the parameters that some cats (A) are televisions (C). This is because in the structure of the syllogism invoked (i.e. III-1) the middle term is not distributed in either the major premise or in the minor premise, a pattern called the "[[fallacy of the undistributed middle]]". Because of this, it can be hard to follow formal logic, and a closer eye is needed in order to ensure that an argument is, in fact, valid.<ref>{{Cite book|last=Lundberg|first=Christian|title=The Essential Guide to Rhetoric|publisher=Bedford/St. Martin's|year=2018|pages=39}}</ref>

Determining the validity of a syllogism involves determining the [[distribution of terms|distribution]] of each term in each statement, meaning whether all members of that term are accounted for.

In simple syllogistic patterns, the fallacies of invalid patterns are:

*[[Fallacy of the undistributed middle|Undistributed middle]]: Neither of the premises accounts for all members of the middle term, which consequently fails to link the major and minor term.
*[[Illicit major|Illicit treatment of the major term]]: The conclusion implicates all members of the major term (P&nbsp;– meaning the proposition is negative); however, the major premise does not account for them all (i.e., P is either an affirmative predicate or a particular subject there).
*[[Illicit minor|Illicit treatment of the minor term]]: Same as above, but for the minor term (S&nbsp;– meaning the proposition is universal) and minor premise (where S is either a particular subject or an affirmative predicate).
*[[Fallacy of exclusive premises|Exclusive premises]]: Both premises are negative, meaning no link is established between the major and minor terms.
*[[Affirmative conclusion from a negative premise]]: If either premise is negative, the conclusion must also be.
*[[Negative conclusion from affirmative premises]]: If both premises are affirmative, the conclusion must also be.