Fallacies of Ambiguity

Include equivocation and amphiboly. This fallacies arise from the occurrence of some form of ambiguity in either the premises or the conclusion (or both).

19. Equivocation
Occurs when the conclusion of an argument depends on the fact that a word or phrase is used, either explicitly or implicitly, in 2 different sense in the argument.

Example:
Some triangles are obtuse. Whatever is obtuse is ignorant. Therefore some triangles are ignorant.

A mouse is an animal. Therefore a large mouse is a large animal.

20. Amphiboly
Occurs when the arguer misinterprets an ambigious statement and then draws a conclsion base on this faulty interpretation. The original statement is usually asserted by someone other than the arguer, and the ambiguity usually arise from a mistake in grammar or punctuation. Ambiguity in sentence structure.

Example:
The tour guide said that standing in Greenwich Village, the Empire Sate Building could easily be seen. It follows that the Empire State Building is in Greenwich Village.

John told Henry that he has made a mistake. It follows that John has at least the courage to admit his own mistakes.