Empathy is the ability to feel what someone else is feeling. Often this is an unconscious process, but we train ourselves and our children to do it, too. “Would you want someone to do that to you?” In order to answer that question, you have be able to imagine what the other person is feeling. Empathy is an extension or component of the Golden Rule.
If you’ve never experienced something that the person you want to empathize with, it’s a bit harder. For example, depression is something that is very difficult for people who have never experienced it to imagine. My wife has never experienced it. She tries to empathize with me, but there is only so far she can go
So empathy generally requires some experience with what the other person is experiencing. You can empathize without have felt it, but the amount of empathy you can provide if you’ve been there is twenty times more.
I think that our facial expressions and body language are ways of both conveying the need for and conveying empathy. By mimicking someone else’s facial expressions, we can feel what the other person is feeling. It goes both ways. A physical movement can both express meaning outward and inward. Put your body in a posture, and you’ll feel the feeling. Just as if you feel the feeling, your body assumes the posture.
Empathy works both cognitively and physically. It is what helps us feel connected to others, and to know who is on “our team.” It is a very powerful tool.