What does this quote mean?

“To define is to limit.”

Definitions clarify ideas but can also narrow them, especially when a label is treated as the complete reality of a person or experience.

Source note: The Picture of Dorian Gray, 1891 edition, Chapter 17; Lord Henry answers the Duchess of Monmouth’s question “What are you?” with “To define is to limit.”

“The universe is wider than our views of it.”

Reality exceeds any one viewpoint, so confidence in a perspective should leave room for what has not yet been seen.

Source note: Walden, Conclusion; Thoreau uses the sentence while arguing that familiar human views do not exhaust reality.

“There is nothing either good or bad, but thinking makes it so.”

The line separates events from the judgments people place on them, a useful distinction for thinking about perception and response.

Source note: Hamlet, Act 2, Scene 2; Hamlet says this to Rosencrantz and Guildenstern while explaining that Denmark feels like a prison to him. The line is dramatic dialogue, not a detached psychological proposition by Shakespeare.

“Take nothing on its looks; take everything on evidence. There’s no better rule.”

Appearances are weak evidence; better judgment comes from examining what can actually be supported.

Source note: Great Expectations; Jaggers advises Pip.

“Tell the truth or trump—but get the trick.”

The joke turns moral advice into card-table strategy, making the line funny precisely because truth and tactical winning are compressed into one impossible-sounding rule.

Source note: Pudd’nhead Wilson, Chapter I epigraph; one of the fictional Calendar maxims Twain places before the chapter.

“The devil can cite Scripture for his purpose.”

Even respected language can be quoted selectively, so a citation should be judged by context and purpose rather than authority alone.

Source note: The Merchant of Venice, Act 1, Scene 3.