and effect. if you fall down and bruise your knee, generally you will feel pain. if you go to the doctor and he says, “where does it hurt?”, and you say, “it hurts in my knee, ” then the doctor will take a history. a history is the best way for the doctor to be able to find out whether or not you have pain and the cause of the pain and the nature of the pain. so if you go to the doctor and say, “i fell down and banged my knee on the ground and my knee hurts,” the doctor will say through cause and effect that you 