Related:

• Our species can only survive if we have obstacles to overcome.
  You remove those obstacles. Without them to strengthen us, we will weaken and die....
• Love sometimes expresses itself in sacrifice. -- Kirk, "Metamorphosis," stardate 3220.3.
• The idea of male and female are universal constants. -- Kirk, "Metamorphosis," stardate 3219.8.
• Not one hundred percent efficient, of course ... but nothing ever is.
  -- Kirk, "Metamorphosis," stardate 3219.8....
• We estimate there are millions of planets with intelligent life.
  We haven't begun to map them. -- Kirk, "Metamorphosis", stardate 3219.8....
• It is inconceivable that a judicious observer from another solar system would see in our species -- which has tended to be cruel
  destructive, wasteful, and irrational -- the crown and apex of cosmic evolution....
• A species that enslaves other beings is hardly superior -- mentally or otherwise.
  -- Kirk, "The Gamesters of Triskelion," stardate 3211.7....
• Chang: "Our battles now are ended, Kirk." -- "STVI:TUC", Stardate 9523.8
• Our people don't believe in slavery. -- Kirk, "Bread and Circuses," stardate 4040.7.