Sympathy is the perception of, understanding of, and reaction to the distress or need of another life form. According to David Hume, this sympathetic concern is driven by a switch in viewpoint from a personal perspective to the perspective of another group or individual who is in need. Hume explained that this is the case because "the minds of all men are similar in their feelings and operations" and that "the motion of one communicates itself to the rest" so that as "affections readily pass from one person to another… they beget correspondent movements." Along with Hume, two other men, Adam Smith and Arthur Schopenhauer, worked to better define sympathy. Hume was mostly known for epistemology, Smith was known for his economic theory, and Schopenhauer for the philosophy of the will. An American professor, Brene Brown, views sympathy as a way to stay out of touch with ones emotions. They attempt to make sense out of the situation and see it from the person receiving the sympathy's perception.