Do you believe in UFOs? According to a poll in 2005, 34% of Americans do. In 2007, Japanese Cabinet Secretary Nobutaka Machimura caused quite a stir when he said on TV that UFOs “definitely” exist. But before you answer the question, pause and think about what UFO means. It is actually an abbreviation for “unidentified flying object.” In other words, if there is something in the sky and nobody knows what it is, then it is an UFO. On this interpretation, there are certainly plenty of UFOs, but they could have been weather balloons, atmospheric reflections, and so on. Of course, UFO can also mean an alien spaceship. If this is what is meant, then it is not so clear that there are any.

This example shows that when the meaning of a claim is unclear, it might be impossible to say whether it is true or false. Two people might disagree about the existence of UFOs, but the disagreement is pointless if they are using the term to mean different things. Being clear helps us avoid such verbal disputes. The UFO example also illustrates a crucial habit we should cultivate if we want to become a better thinker—before accepting a claim, pause to think about what it means and whether we understand what it says. We are bombarded with sound bites and slogans every day, and we should avoid accepting them uncritically.

Consider the popular idea that the economy should be a free market without government interference. Before deciding whether we agree or disagree, ...

Get An Introduction to Critical Thinking and Creativity: Think More, Think Better now with the O’Reilly learning platform.

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.