“The self-knowledge which refuses a flattering opportunity, when it comes under circumstances which do not ensure that it shall be successfully accepted, is among the most valuable of talents.”

Treating the ability to decline an ill-timed opportunity as a valuable form of self-knowledge · Letter to his parents, 16 November 1856

• Courage
• Truth

“Modern philosophy is thankful for the facts, and waits till they make a bed for themselves.”

Arguing that evidence should be allowed to shape theory rather than being forced into it · Notes of an Address to Medical Students, 1856

• Nature
• Truth

“The temper in which we perceive a fact to be accounted for is very different from that in which we construct a theory to explain it.”

Distinguishing observation from the theories we build around it · Lecture, Nature of Poetry, 1857

• Truth