Illicit conversion

Illicit conversion

An illicit conversion is the invalid inversion of a A- or O-type proposition. It can also be defined as an argument which entails the arbitrary assignment of a specific trait of a set to one of its subsets.

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The basic forms of the illicit conversion are as follows:

"All A are B."

"Therefore, all B are A."

"Not all A are B."

"Therefore, not all B are A."

Examples

"All dolphins are mammals."

"Therefore, all mammals are dolphins."

"Some pupils are not undergraduates."

"Therefore, some undergraduates are not pupils."

"All squares are rectangles."

"Therefore, all rectangles are squares."

"All drinks are liquid."

"Therefore, all liquids are drinks."

ource

[http://www.fallacyfiles.org/illiconv.html Fallacy Files -Illicit Conversion]


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