The line-drawing fallacy occurs when an arguer concludes that terms referring to different positions on a spectrum wherein there is no definitive point that separates the terms, are therefore meaningless, and that any supposed distinction between them should be ignored.

The fallacy is also sometimes called the fallacy of the beard because of the classic example of a man who has not shaved for a whole day, and thus has stubble but not a beard. If that man continues to refrain from shaving for an entire year, he definitely ends up with a beard. But at what point in the course of that year did he change from having merely stubble, to having an actual beard? On day 5? Day 10? Day 20?

The line-drawing fallacy exploits this phenomenon of labels that fall along a spectrum, to disregard the labels. It would be like saying the distinction between "unbearded" and "bearded" is a meaningless one because there is not precise point at which the first term stops and the second term begins.

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