Read the excerpt from "Politics and the English Language" by George Orwell. But if thought corrupts language, language can also corrupt thought. A bad usage can spread by tradition and imitation, even among people who should and do know better. The debased language that I have been discussing is in some ways very convenient. Phrases like a not unjustifiable assumption, leaves much to be desired, would serve no good purpose, a consideration which we should do well to bear in mind , are a continuous temptation, a packet of aspirins always at one’s elbow. Which type of evidence is used in this excerpt?