One thorn of experience is worth a whole wilderness of warning.

• experience

No man can produce great things who is not thoroughly sincere in dealing with himself.

• self respect

And I honor the man who is willing to sink

Half his present repute for the freedom to think,

And, when he has thought, be his cause strong or weak,

Will risk t' other half for the freedom to speak.

• reputation
• freedom
• free speech
• risk