Here a pretty simple puzzler. Can you find a mistake in Alex‘s logic (taken from an October 9, 2000 strip)?
The usual Freakonomics schwag to the first commenter to post a nice, quotable answer.
(Hat tip: Sparky Clark)
Freakonomics Quiz: Doonesbury Logic
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All independents having a mind of their own does not imply that non-independents do not have their own minds. The first statement says nothing about non-independents.
Being is confusing the meaning of independent. Independent is being used in two different ways. One as a political party and one as having a mind of your own. The latter is not exclusive to your party.
She’s using bad conditional logic. If independent -> mind of your own = if no mind of your own -> not independent. From the first statement, you can’t infer anything about people who AREN’T independent.
It is an example of false induction.
This is a crow and it is black; that is a crow and it is black; therefore all crows are black
“If you’re an independent, then you have a mind of your own,” doesn’t imply the inverse, “If you’re not an independent, then you don’t have a mind of your own.” Here’s a more obvious example of this logical fallacy: “All fish swim. Michael Phelps is not a fish. Therefore, Michael Phelps doesn’t swim.”
equivocation!
Alex, its the contrapostive, “NOT having a mind of your own implies that you are NOT an independent”, that is equivalent to “being and independent means that you have a mind of your own” not the converse.
Of course, many independents don’t have a mind at all, let alone a mind of their own.
“All fish swim. Michael Phelps is not a fish. Therefore, Michael Phelps doesn’t swim.” I now have a new example for this type of logic.