Around 1830, Arthur Schopenhauer began a manuscript on the tricks people use to win an argument. It was published after his death, in 1864, and is known as Eristische Dialektik or Die Kunst, Recht zu behalten, The Art of Being Right. Trick number 8 reads: Den Gegner zum Zorn reizen: denn im Zorn ist er außer Stand, richtig zu urteilen und seinen Vorteil wahrzunehmen. Make your opponent angry, because in anger he cannot judge correctly or protect his own interests. Schopenhauer explains how it is done. Man bringt ihn in Zorn dadurch, daß man unverhohlen ihm Unrecht tut und schikaniert und überhaupt unverschämt ist. You treat him unfairly in the open, you harass him, and you are generally insolent. Trick number 27 also uses anger. If the opponent suddenly becomes angry at an argument, press that argument hard. The anger suggests that you have touched the weak side of his thinking.