Derek Sivers recounts a woman who made several good points, then ruined her argument by declaring, "Ugh! Those people are just so stupid!!" She could have aimed the insult at Southerners, Northerners, Liberals, Conservatives, Chinese, or Americans. The target does not matter. What matters is that the outburst showed she had stopped thinking.
Sivers argues that there are no smart people or stupid people, only people being smart or being stupid at a given moment. Being smart means thinking things through and seeking the real answer rather than the easiest one. Being stupid means avoiding thought by jumping to conclusions.
Jumping to a conclusion, he writes, is like quitting a game: you lose by default. That is why saying "I don't know" is usually the smart response, because it refuses to leap to a premature judgment. When someone declares that others are stupid, they have stopped thinking, and they say it because the snap judgment is satisfying.
So if you decide someone is stupid, you are not thinking, and therefore you are not being smart. The logic closes neatly: smart people do not think others are stupid.
Source: Hacker News · Summarized by HeadlinesBriefing