AmbiguityType: Informal Fallacy
President Clinton should have been impeached only if he had sexual relations with Monica Lewinsky.
As a feature of language, ambiguity occurs when a word or phrase has more than one meaning. For instance, the word "note" can mean either:
In fact, the Random House College Dictionary lists twenty meanings of "note", though one of these is archaic. Even the part of speech is ambiguous, since "note" can be either a noun or verb. This situation is not at all unusual, and "note" is not a particularly ambiguous word. Opening any dictionary at random will confirm that it is the rare word that is not ambiguous. In fact, ambiguity tends to increase with frequency of usage, and it is rarely-used technical terms that are unambiguous. For instance, "is" is highly ambiguous and has, as a result, caused much mischief in metaphysics, and even politics.
Because of the ubiquity of ambiguity in natural language, it is important to realize that its presence in an argument is not sufficient to render it fallacious, otherwise, all such arguments would be fallacious. Most ambiguity is logically harmless, a fallacy occurring only when ambiguity causes an argument's form to appear validating when it is not. Consider the Example: If the phrase "sexual relations" is being used univocally, then it has the following form:
p only if q.
This is, of course, a version of the validating form Modus Tollens. However, if "sexual relations" has one meaning in the first premiss, and a different meaning in the conclusion, then it is used ambiguously, and the argument has the following non-validating form:
p only if q.
Such an argument commits a Fallacy of Ambiguity (specifically, Equivocation), because it may seem to have a validating form when the audience interprets the ambiguous phrase univocally. Thus, arguments which commit the Fallacy of Ambiguity can seem to be valid.
While not always a fallacy, ambiguity is frequently misleading. For instance, in the much publicized statement by President Clinton:
I did not have sexual relations with that woman, Miss Lewinsky.
Source: Howard Kurtz, Spin Cycle: Inside the Clinton Propaganda Machine (Touchstone, 1998), p. 297.
This claim was testimony, rather than argument, so it cannot be fallacious. However, it is now clear that it was intended to snare the listener into concluding, falsely, that there was no sexual relationship between the President and Miss Lewinsky. The ambiguity came from the phrase "sexual relations", which has a broad and narrow meaning:
As he later admitted, President Clinton had had "sexual relations" with Miss Lewinsky in the broad sense (1), and he was denying it only in the narrow sense (2).
Unintentionally ambiguous statements are frequently sources of humor, especially when one of the possible meanings is ludicrous. For example:
Source: Jay Leno (compiler), More Headlines: Real but Ridiculous Samplings from America's Newspapers (Warner Books, 1990), p. 8.
S. Morris Engel, Fallacies and Pitfalls of Language: The Language Trap (Dover, 1994), Chapter 2.
Kent Bach, "Ambiguity", Routledge Encyclopedia of Philosophy