In both the soul and city, Plato uses justice as the right ordering of the other parts and virtues, unifying them. To further show his emphasis on wisdom and the relationship between the virtues, he says "Isn't it proper for the calculating part to rule, since it is wise and has forethought about all of the soul" (Plato 441E). A third belief is that personal happiness is an adolescent view of happiness. He believed that communal happiness is the truth. This is seen throughout his city. Everyone is assigned one art to perform to the highest ability for the greater good of the community. In sum, Socrates believed that knowledge is virtue which leads to happiness, that the virtues are all connected, and that communal happiness is the goal rather than individual happiness. .
Aristotle strongly opposed his master when it came to these points but before his rebuttals are unmasked it is important to get a sense of where the two philosophers resemble one another. Like Plato, Aristotle strongly believed that happiness is more than just simple pleasure. "Happiness does not consist in amusement. It would be strange if our end were amusement, and if we were to labor and suffer hardships all our lives merely to amuse ourselves (Aristotle,1176B). He also argues that happiness is the highest good. He says that, "The highest good must be something final.seems to apply to happiness above all else: for we always choose happiness as an end in itself and never for the sake of something else (Aristotle, 1097A)." He argues, as his teacher did before him, that virtue is essential in achieving happiness, that without the good, one can never fully reach this end. Now we enter into where the philosophers differentiate. .
Aristotle splits virtue into two parts: moral virtues and intellectual virtues. Moral virtues require practical thinking involving reasoning while intellectual virtues need contemplative thinking.
