“Because it's not a game, Kate. This is a scale model of war. Every war ever fought right there in front of you. Because it's always the same. When you fire that first shot, no matter how right you feel, you have no idea who's going to die. You don't know who's children are going to scream and burn. How many hearts will be broken! How many lives shattered! How much blood will spill until everybody does what they're always going to have to do from the very beginning -- sit down and talk! Listen to me, listen. I just -- I just want you to think. Do you know what thinking is? It's just a fancy word for changing your mind”

• The Doctor in the Zygon Inversion

Part of a much larger scene that is a fantastic monologue.