Equivocation

When I was writing my blog about types of fallacies last week, I realized that I had given hardly any attention to fallacies of ambiguity, while I regularly explained fallacies of presumption and relevance. This is not surprising for in Arp et al. 2019, 43 fallacies of presumption and 34 fallacies of relevance are discussed but only 16 fallacies of ambiguity. If this is a measure, then the latter are by far in the minority, which doesn’t involve, however, that they are less frequent. The only fallacy of ambiguity I discussed is the conjunction fallacy, while I mentioned the sorites fallacy only in passing. So, a good reason to treat such a fallacy now.
I think – though it is just a guess – that one of the most common fallacies of this type is the fallacy of equivocation. It often appears in discussions and political speeches. This fallacy involves that a word or phrase is used with different meanings in an argumentation. You may think: Of course, that’s a matter of false reasoning. However, the distinctions between the different meanings are often subtle and you may not see them or you must be a logical expert, and maybe also the speaker didn’t notice the mistake. Here is a clear case: “The loss made Jones mad [= angry]; mad [= insane] people should be institutionalized; so Jones should be institutionalized.”) [1] “Mad” has two different meanings here, so the conclusion doesn’t follow. Here is another rather simple example of this type: Only man [human] is rational, and no woman is a man [male]. Therefore, no woman is rational. [2]
However, an equivocation can be rather subtle, as said. Bertha Alvarez Manninen starts her explanation of the fallacy in Arp et al 2019 with an equivocation by Pres. John F. Kennedy, who said: “And so my fellow Americans, ask not what your country can do for you, ask what you can do for your country.” The equivocation is here, so Manninen, that first “country” refers to the elected officials and then to something like your homeland, nation, or your fellow citizens.
The equivocation is even more subtle in a case analysed by the philosopher Mary Anne Warren and discussed by Manninen: I quote (pp. 262=3:

“Typically, a common pro-life argument runs as follows:

(1) All human beings have a right to life.
(2) A fetus is a human being.
(3) Therefore, the fetus has a right to life.

Warren … argues that an equivocation is made here with the term ‘human being’. In the first premise, [it] is a moral term, denoting the kinds of beings who are ‘a full-fledged member of the moral community.’… In the second premise, [it] is a biological term, denoting a member of the species Homo Sapiens. … A useful tool for determining whether an argument commits the fallacy of equivocation can be applied here: replace the premises of the argument explicitly with the term having the same meaning and then gauge whether the argument is successful.

(1) All human beings (in the moral sense) have a right to life.
(2) A fetus is a human being (in the moral sense).
(3) Therefore, the fetus has a right to life.

Seen this way, Warren argues that the pro-life argument commits the begging of the question fallacy in Premise 2 by assuming the very thing that needs to be argued [, namely] whether the fetus is a human being in the moral sense of the term... That is not to say that the fetus isn’t such a being but rather that this is the very thing that need to be argued rather than assumed.”

So far the quotation. Of course, alternatively one can add “(in the genetic sense)” in the premises instead of “(in the moral sense)”, etc. What this example makes clear is that discovering an equivocation often is hard, but it is necessary in order to get a meaningful debate. Its obscurity makes it an easy instrument of manipulation for politicians and orators by using ambiguous words or by using words in an ambiguous way.
However, you don’t need to be a politician, orator or a simple member of their public to commit the fallacy of equivocation. Also philosophers do, although they are supposedly experts in argumentation. Then we call it a category mistake. So, Heraclitus committed the fallacy of equivocation, or made a category mistake, when he said that you cannot step twice in the same river. By saying so, he confused the river and the water in the river. Another example is to confuse the mind and the brain. It is not our brain that thinks but our mind does. Also Descartes committed this fallacy, when he saw the mind sometimes as a thing and sometimes as a mental capacity.

Sources
- The numbers in brackets [ ] refer to the sources: Follow the links.
- Robert Arp; Steven Barbone; Michael Bruce (eds.), Bad arguments. 100 of the most important fallacies in Western philosophy. Oxford, etc.: Wiley Blackwell, 2019. Esp. Bertha Alvarez Manninen, “Equivocation”, pp. 261-5.