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.”

“Opinion appears to you to be darker than knowledge, but lighter than ignorance?”

Opinion is treated as an intermediate state: it is not complete ignorance, but it also lacks the clarity and stability of knowledge.

Source note: The Republic, Book V; Socrates places opinion between knowledge and ignorance in the argument about what each apprehends.

“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.

“The world is a perpetual caricature of itself.”

Social appearances repeatedly exaggerate or contradict reality, making ordinary life look like an ongoing parody of its own pretensions.

Source note: Soliloquies in England, “Dickens”; Santayana uses caricature to describe the gap between living reality and conventional masks.

“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.

“The unexamined life is not worth living.”

Socrates links a worthwhile human life with reflection on beliefs, conduct, and reasons rather than unexamined routine.

Source note: Apology 38a; wording varies by translation.