There is evidence that a preference for beautiful faces emerges early in child development, and that the standards of attractiveness are similar across different genders and cultures. Symmetry is also important because it suggests the absence of genetic or acquired defects.
Although style and fashion vary widely, cross-cultural research has found a variety of commonalities in people’s perception of beauty. The earliest Western theory of beauty can be found in the works of early Greek philosophers from the pre-Socratic period, such as Pythagoras. The Pythagorean school saw a strong connection between mathematics and beauty. In particular, they noted that objects proportioned according to the golden ratio seemed more attractive. Ancient Greek architecture is based on this view of symmetry and proportion.
Plato considered beauty to be the Idea (Form) above all other Ideas. Aristotle saw a relationship between the beautiful (to kalon) and virtue, arguing that “Virtue aims at the beautiful.”