What does this quote mean?

“This above all: to thine own self be true.”

Polonius frames integrity as consistency between inward conviction and outward conduct, although the advice belongs to a fallible fictional counselor.

Source note: Hamlet, Act 1, Scene 3; Polonius gives Laertes this advice before Laertes leaves for France.

“He that walketh uprightly walketh surely.”

Consistent upright conduct reduces the need to maintain conflicting stories or hidden motives.

Source note: Proverbs 10:9 in the King James Version; the opening clause is quoted here.

“My life is for itself and not for a spectacle.”

The line rejects living primarily for public display and treats a life’s inward reality as more important than performing goodness for outside approval.

Source note: Self-Reliance, in Emerson’s discussion of genuine action rather than virtue performed as spectacle.

“Nothing is at last sacred but the integrity of your own mind.”

Emerson places inner integrity above conformity, arguing that a person should examine inherited standards rather than surrender judgment merely because they are socially approved.

Source note: Self-Reliance, in the passage beginning with Emerson’s argument for nonconformity.

“It is above all things necessary to form a true estimate of oneself.”

A realistic estimate of one’s abilities and limits supports both confidence and humility, reducing the instability that comes from either self-contempt or exaggerated self-belief.

Source note: Of Peace of Mind, section VI; the passage begins Seneca’s practical advice about matching undertakings to one’s actual powers and disposition.

“What a man thinks of himself, that it is which determines, or rather indicates, his fate.”

Thoreau argues that private self-judgment can become a powerful constraint or permission, shaping choices more strongly than public opinion alone.

Source note: Walden, “Economy,” in the passage contrasting public opinion with a person’s own private opinion of himself.