"The capacity to
(a) be affected by and share the emotional state of another,
(b) assess the reasons for the other’s state, and
(c) identify with the other, adopting his or her perspective.
This definition extends beyond what exists in many animals, but the term “empathy” … applies even if only criterion (a) is met".
de Waal F.B.M. 2008. Putting the altruism back into altruism: the evolution of empathy. Annual Review of Psychology 59: 279-300.