False analogy

Name of fallacy False analogy
Type Irrelevant Argument, Informal Argument
Description Argument by analogy
FormFalse analogy consists of an error in the substance of an argument (the content of the analogy itself), not an error in the logical structure of the argument. In an analogy, two concepts, objects, or events proposed to be similar in nature (A and B) are shown to have some common relationship with another property. The premise is that A has property X, and thus B must also have property X (due to the assumed similarity of A and B). In false analogies, though A and B may be similar in one respect (such as color) they may not share property X (e.g. size). Thus, even if bananas and the sun appear yellow, one could not conclude that they are the same size.
Treatment Dealt with by examining the alleged analogy in detail and pointing out where it breaks down. If the analogy is forced then the absurdity of the analogy can best be exposed by showing how many other analogies supporting different conclusions might have been used.