How we change what others think, feel, believe and do

Petitio Principii

Techniques > General persuasion > The Art of Being Right > Petitio Principii

Description | Example | Discussion | See also

Description

If your opponent requires you to admit something from which the point in dispute will immediately follow, you must refuse to do so, declaring that it is a petitio principii. For he and the audience will regard a proposition which is near akin to the point in dispute as identical with it, and in this way you deprive him of his best argument.

Example

You ask me if I was out of the house, but you might conclude from this that I did not know what was happening there, but believe me I have eyes and ears that you do not know about.

Does she understand the detail? Maybe not, but that does not mean she is ignorant of the key facts.

Discussion

Petitio Principii is the logical fallacy of assuming the conclusion in the premises, or begging the question.

It can be an effective technique to use the Latin names for fallacies in conversation as this shows your greater command of the subject and will dissuade them from using deceptive methods.

'Petitio Principii' is the twenty-second of Schopenhauer's stratagems.