Negative emotions like hatred destroy our peace of mind.
— Matthieu Ricard
Mind training is based on the idea that two opposite mental factors cannot happen at the same time. You could go from love to hate. But you cannot, at the same time - toward the same object, the same person - want to harm and want to do good.
Empathy is the faculty to resonate with the feelings of others. When we meet someone who is joyful, we smile. When we witness someone in pain, we suffer in resonance with his or her suffering.
I got really involved in science research and the science of meditation.
Neuroscience has proven that similar areas of the brain are activated both in the person who suffers and in the one who feels empathy. Thus, empathic suffering is a true experience of suffering.
That's what Buddhism has been trying to unravel - the mechanism of happiness and suffering. It is a science of the mind.