If you read a story that really involves you, your body will tell you that you are living through the experience. You will recognize feelings that have physical signs - increased heart rate, sweaty palms, or calm, relaxed breathing and so on, depending on your mood. These effects are the same you would feel in similar real-life experiences - fear, anger, interest, joy, shame or sadness. Amazingly, you can actually 'live' experience without moving anything but your eyes across a page.