Interpret: avoidable errors and use of words

The passage says that people, whether scientists or ordinary persons, often make mistakes that could have been avoided because they do not reason correctly. One important cause is the careless use of words.

Explanation

• Avoidable errors. Individuals and groups both fall into errors of reasoning. Such errors are not forced on us by ignorance of facts; they come from poor thinking.
• Many reasons, one discussed. The writer says there are many reasons but takes up only one: the same word can mean different things to different people.
• Examples. A word like "intelligence" is used by a psychologist in a technical way, and by an ordinary person for general cleverness. "Oxygen" means a particular chemical element to a chemist but only "the part of air we breathe" to a layman. When people argue using one word in different senses, they do not really disagree about facts; they misunderstand each other.
• Failure to differentiate. Words often do not separate clearly the different varieties of the "same" thing. One word covers several things that differ, so we wrongly treat them as identical and reach false conclusions.

Message

To think correctly we must be clear about what words mean, notice when a word is used in more than one sense, and avoid assuming that one name means one thing.