Contrary to the rationalists, Hume believes that reason is not the motive of the will, but simply the slave of the passions. Morality is not within the immediate reach of reason, because reason alone cannot desire anything but simply find the means to actualize the end; It is passion that desires and dictates our wills. The fundamental assumption Hume made in his moral philosophy is that human beings are intrinsically motivated by pleasure. Therefore, virtues and vices are measured by pain and pleasure. Moral sense theory states that we acquire concepts of moral right and wrong by experiencing the satisfaction of approval and the pain of disapproval. As for the perception of virtues and vices, Hume argues that sympathy, or theory of mind, plays an important role. Characters useful to human society are virtues, because these socially beneficial actions would please observers out of sympathy and therefore arouse their approval, which in turn brings pleasure to the one doing the good deed. On the contrary, character traits destructive to society are vices, because vicious acts can...