Logic: Logical Fallacies (3)

1. Circular Reasoning: Where someone attempts to prove his conclusion by simply restating it. He says “P is true because Q is true, and Q is true because P is true.

• Jimmy: Dad, why do I have to learn logic? Dad: Because it will help to develop your mind. Jimmy: Why will it develop my mind? Dad: Because it will help you think better.

2. Equivocation: Where the meaning of a word is changed in the middle of an argument.

• Dad: “Son, when you grow up I want you to always be a responsible young man.” Son: “But Dad, I am already very responsible. Whenever something breaks around here, it seems as if I am always responsible.”

3. Loaded Question: Where someone asks one question which assumes the answer to a second question.

• Neighbor: “Why do you like to disturb the neighborhood by playing your music so loud everybody can hear it a mile away?” [Does the neighbor really like to disturb the neighborhood?]

4. Part-to-Whole: Where someone asserts that what is true of part of something must also be true of the whole thing together.

• Child: “Mommy, why is this feather pillow so heavy? It only has feathers in it and little feathers weigh hardly anything.”

5. Whole-to-Part: Where someone asserts that what is true of something as a whole must also be true of each of its parts. This is the reverse of the part-to-whole fallacy.

• If our bag of potato chips won’t float when I throw it in the pond, why will one of my potato chips float by itself?

6. Either-Or: Where someone asserts that we must chose between two things, when in fact we have more alternatives.

• Either you believe in evolution, or you are totally irrational. You say you don’t believe in evolution, so you must be irrational.

Making Assumptions