Empathy and Pathology
Empathy is the ability to understand and share in how other people are feeling.
A mirror neuron is a neuron that fires both when an animal acts and when the animal observes the same action performed by another. Thus, the neuron "mirrors" the behavior of the other, as though the observer were itself acting. Such neurons have been directly observed in human and primate species, and birds.
Empathy can be used to gain the trust of others. Further, it is easier to help people that one empathizes with.
Empathy can enhance dialectic. In keeping with this, when used as a tool to understand what someone is thinking, rather than just for what they are feeling, empathy can make it easier to steelman an argument.
There are many aspects of empathy that, if not shortcomings, color it differently than many imagine it.
Empathy can fall victim to the identifiable victim affect. Additionally, when directed in a biased way, empathy can be used to reinforce those biases and in-group loyalty. Finally, pathological actors can manipulate others by invoking their empathy.