Levels of empathy
0) Poking a needle in my hand — hurts. 1) If I poke a needle in your hand — it must hurt. 2) If someone else pokes a needle in your hand — it must hurt the same way as when I do it. 3) You feel the same fear of cockroaches I feel of dogs. 4) You are disgusted by this book the same way I'm disgusted by that music.