Critical Thinking Toolkit: The Fallacy of Equivocation

This is one of many brief articles I am writing about how to avoid fallacious patterns of thinking. Here, we briefly discuss the fallacy of equivocation. Before I try to define it, it will be helpful to see an example of the fallacy in action. (I take this example out of the Wikipedia page for this fallacy, because I find it particularly helpful)

  • Only man is rational,
  • No woman is a man,
  • Therefore, no woman is rational.

If you use only formal logic, this argument is actually correct. It follows the following strict formula:

  • If X, then Y.
  • X.
  • Therefore, Y.

In our example, X stands for “being rational” and Y stands for “being a man.” Only man is rational – for it wouldn’t be right to say that earthworms, for instance, are rational beings. And it is true that you cannot simultaneously be fully male and fully female (this is true regardless of your political beliefs on the topic of gender). But we know that there are rational women (in fact, all human beings are rational… at least in the sense that we are capable of thinking rationally). So what did we do wrong here?

The answer is simple. We changed the definition of the word man midway through the argument. When we say only man is rational, by man we really mean mankind – both men and women. But in the second point, we are using man to refer to male human beings only – and not all human beings are male. Since we shifted our definition of the word man midway through our argument, this argument that ‘looks like’ it work doesn’t actually work.

Main Takeaways

The fallacy of equivocation is only likely to occur in a situation where one of the most important words involved in your discussion can have multiple definitions in different contexts (like man) or if the word itself is comparative and thus has a context-dependent meaning (like small). Whenever words like these are being used, be careful to ensure you are using them in the same manner throughout the discussion.

How To Overcome the Fallacy

Suppose that someone accuses you of the fallacy of equivocation. How do you overcome this objection? Actually, the solution is quite simple. All you have to do is provide a clear definition of the word in question. It might happen that some of the points you were trying to make become false when you make your definition more specific, and it may equally well be the case that the person accusing you of the fallacy misunderstood what you meant in your use of language. Things like this happen occasionally – people are imperfect and sometimes don’t realize when they use a word in a subtly different way. Nonetheless, it is important that we call each other out when we perceive equivocation going on, because like all logical fallacies, it can be used in extremely harmful ways.

Example for the Reader

For those who want to better understand the fallacy of equivocation, try to spot the equivocation in the following example. If you want to check your work, feel free to email me ( and I’ll let you know if you’ve understood the main point correctly!


  • I am Greek.
  • Greek is a language.
  • Therefore, I am a language.

3 thoughts on “Critical Thinking Toolkit: The Fallacy of Equivocation

  1. Some would say that having extra sex chromosomes and/or both genitalia would make one both male and female at the same time


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