Related:

• The actual theory is that all life forms evolved from the lower levels to the more advanced stages.
  -- Spock, "Let That Be Your Last Battlefield," stardate 5730.2....
• Spock: "Yet you are pumping him full of your noxious potions, as if he were a human.
  -- "Let That Be Your Last Battlefield", Stardate 5730.6....
• We are not killers. -- Chekov, "Let That Be Your Last Battlefield," stardate 5730.6.
• No one knows how he'll act under pressure. -- Sulu, "Let That Be Your Last Battlefield," stardate 5730.
  2....
• You're from the planet Earth. There is no persecution on your planet.
  There was persecution on Earth once; I remember reading about it in my history class....
• The combination of a number of things to make existence worthwhile.
  Yes, the philosophy of 'nome,' meaning 'all.' -- Spock and Lincoln, "The Savage Curtain," stardate 5906....
• Are you sure you won't change your mind? Is there something wrong with the one I have?
  -- Gillian & Spock, "The Voyage Home," stardate 8390....
• Physical laws simply cannot be ignored. Existence cannot be without them.
  -- Spock, "Spectre of the Gun," stardate 4385.3....
• Possible existence of a parallel universe has been scientifically conceded.
  -- Spock, "The Alternative Factor," stardate 3088.7....