In Alice, the caterpillar asks, who are you, who are you; which is a very good question, especially when put by a caterpillar. Bit of a Zen Koan, bit of a Taoist mystery, who are you? Who am I?
In groups with identity the question becomes who are we in relation to them.
Empathy is the word used to describe how we relate to what others are feeling.
So they experience pain, we suffer sympathetically with them and in the brain our pain receptors spark up.
According to an article I read recently this reaction can lead to us(humanity) doing terrible things to people who are not us. This is because we empathise most with those we regard as us and dehumanise those out-with our group.
As we suffer sympathetic pain, so we can also feel sympathetic joy. We feel when our side wins, when our friends do well.
Metta bhavana is a Buddhist meditation method used to overcome the idea of the us and the them, the you and the me, the inner and the outer. It starts with the self and is shared with the other. The method aims to create sympathetic joy in the self, that can be shared with all others.
The article titled, Empathy: Over rated? was written by Spencer Kornhaber who writes for the The Atlantic.com