The tendency of modern scientific teaching is to neglect the great books, to lay far too much stress upon relatively unimportant modern work, and to present masses of detail of doubtful truth and questionable weight in such a way as to obscure principles.

Meaning: Coming close to an act is different from completing it. The saying draws a sharp line between almost and actually, but it should not excuse attempts, dangerous conduct or the consequences of a near miss.

Meaning: Another worker can often find something to improve in work already considered finished. The second barber’s remaining task suggests that completion depends on standards and perspective, without proving that earlier work was careless or endless correction is necessary.

Meaning: Someone's belief may have been produced by what they want to be true, rather than by good evidence that it is true.