Equivocation

Type: Ambiguity

Example:

The elements of the moral argument on the status of unborn life…strongly favor the conclusion that this unborn segment of humanity has a right not to be killed, at least. Without laying out all the evidence here, it is fair to conclude from medicine that the humanity of the life growing in a mother's womb is undeniable and, in itself, a powerful reason for treating the unborn with respect.

Source: Helen M. Alvaré, The Abortion Controversy (Greenhaven, 1995), p. 24.

Analysis

Counter-Example:

The humanity of the patient's appendix is medically undeniable.
Therefore, the appendix has a right to life and should not be surgically removed.

Exposition:

Equivocation is the type of ambiguity which occurs when a single word or phrase is ambiguous, and this ambiguity is not grammatical but lexical. So, when a phrase equivocates, it is not due to grammar, but to the phrase as a whole having two distinct meanings.

Of course, most words are ambiguous, but context usually makes a univocal meaning clear. Also, equivocation alone is not fallacious, though it is a linguistic boobytrap which can trip people into committing a fallacy. The Fallacy of Equivocation occurs when an equivocal word or phrase makes an unsound argument appear sound. Consider the following example:

All banks are beside rivers.
Therefore, the financial institution where I deposit my money is beside a river.

In this argument, there are two unrelated meanings of the word "bank":

1. A riverside: In this sense, the premiss is true but the argument is invalid, so it's unsound.
2. A type of financial institution: On this meaning, the argument is valid, but the premiss is false, thus the argument is again unsound.

In either case, the argument is unsound. Therefore, no argument which commits the fallacy of Equivocation is sound.

Funny Fallacy:

Newspaper headlines, because they are so short, have to be written carefully to avoid equivocation; here are some amusing examples which failed to do so:

Marijuana Party Launches Local Campaign

Police ID Wendy's Finger Owner

Gene Marker May Show Prostate Cancer Risk

White House Mum on Destroyed CIA Tapes

Subfallacy: Ambiguous Middle

Sources:

• S. Morris Engel, With Good Reason: An Introduction to Informal Fallacies (Fifth Edition), St. Martin's, 1994.
• Lawrence H. Powers, "Equivocation", in Fallacies: Classical and Contemporary Readings, edited by Hans V. Hanson and Robert C. Pinto, Penn State Press, 1995, pp. 287-301.

Resources:

Abbott & Costello, "Who's On First?":

• Listen to the classic comedy sketch.
• Read the classic comedy sketch.

Analysis of the Example:

This argument equivocates on the word "humanity"—"the condition of being human"—which means "of, … or characteristic of mankind" (The Random House College Dictionary, Revised Edition, 1975). The two relevant meanings here are:

1. "of…mankind", meaning being a member of the human species.
2. "characteristic of mankind". For instance, the "human heart" is "human" in this sense, since it is not a human being, but is the kind of heart characteristic of human beings.

Applying this to Alvaré's argument, it is true that the "humanity" of an embryo or fetus is medically undeniable, in the second sense of "human"—that is, it is a "human embryo or fetus". It is, however, an equivocation on "human" to conclude, as Alvaré did, that it "has a right not to be killed". Parts of the human body are "human" in this sense, but it is only a whole human being who has a right to life.