How does to know better than to do <something> effect/imply/induce the definition:

to be wise or moral enough not to do <something>?

Please explain the steps, thought processes; I’d like to try to resolve this myself in the future? I realise that this may seem a basic question, but I want to confirm because the definition above connotes positivity, whereas this use by the Spectator alludes to slyness?

  • 1
    It's still wisdom that's at the heart of it. They are wise enough to know that doing that something isn't the way to a solution- whether that solution is getting a suspect to reveal information or just doing something the "right" way instead of the "wrong" way doesn't matter.
    – Jim
    Oct 12, 2014 at 16:29
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    Consider the standard scolding a child receives when they've done something wrong: "Billy I'm surprised at you! You should know better [than to do that.]"
    – Jim
    Oct 12, 2014 at 16:32
  • Get a better dictionary and many of your issues would be solved.
    – TimR
    Oct 12, 2014 at 16:52

2 Answers 2


This idiom first shows up in the 1680s, and at that time it has two forms:

A. the modern version know better than to, and
B. a fuller version know better things than to.

A and B trot along side-by-side for about a hundred years, but towards the end of the 18th century B drifts out of use.

The idiom is founded on long established expressions (they go back at least to Chaucer):

  1. know [something] better than [something else], meaning to be aware of something which is better than something else

  2. know [something] better than [someone else], meaning to be more knowledgeable about something than someone else is.

The B version obviously has sense 1: know things to do which are better than what you are doing or proposing to do. I would guess the A version to have been originally just a shorter version of the B version, with better understood as a nominal something better. But I suspect it finally superseded B because it also accommodated understanding in sense 2: you are too knowledgeable to do what you are doing or proposing to do


To know better than to {verb infinitive} means that one knows it would be ill-advised to {verb}. That is, the action is either morally wrong or it will not yield the desired result.

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