You use a metaphor to describe some concept. The metaphor isn’t the thing you describe - it’s just a tool that you use. But someone takes the metaphor, and runs with it, making arguments that are built entirely on metaphor, but which bear no relation to the real underlying concept. And they believe that whatever conclusions they draw from the metaphor must, therefore, apply to the original concept.

— Mark Chu-Carroll, Metaphorical Crankery: a bad metaphor is like a steaming pile of …