Related:

• Possible existence of a parallel universe has been scientifically conceded.
  -- Spock, "The Alternative Factor," stardate 3088.7....
• No one may kill a man. Not for any purpose. It cannot be condoned.
  -- Kirk, "Spock's Brain," stardate 5431.6....
• Sometimes pain can drive a man harder than pleasure.
  -- Kirk, "the Alternative Factor," stardate 3088.7....
• Spock: "Captain, I will not be coming with you." Picard
  Ambassador--" Spock: "The reason for my coming here has never been more clear....
• It would be illogical to kill without reason. -- Spock, "Journey to Babel," stardate 3842.4.
• Life and death are seldom logical. But attaining a desired goal always is.
  -- McCoy and Spock, "The Galileo Seven," stardate 2821.7...
• Data: "Ambassador Spock, may I ask a personal question?
  Spock: "Please." Data: "As you examine your life, do you find that you have missed your humanity?...
• Spock: "May I assist you, Commander? I have had some experience in these matters.
  Data: "By all means, Ambassador." -- "Unification II", Stardate 45245.8...
• I object to intellect without discipline; I object to power without constructive purpose.
  -- Spock, "The Squire of Gothos," stardate 2124.5....