Personal inconsistency

Personal inconsistency (tu quoque—"you too") is when you say the other person's point doesn't count because they don't always follow it themselves. But that doesn't make their point wrong. A smoker can still be right that smoking is bad; someone who flies can still be right that we should reduce carbon emissions. The fallacy is to attack the person's consistency instead of the argument. The claim stands or falls on its merits.

Examples

• You say we should use less plastic, but you still buy bottled water. So your argument doesn't count.

• He's always late—why should we listen to him about punctuality?

• You're not a vegetarian, so you can't criticise factory farming.

• She uses the product herself, so she's not really against it.