Tao Te Ching, 2

When the people of the world all know beauty as beauty,

                There arises the recognition ugliness.

When they all know the good as good,

                There arises the recognition of evil. (Tao Te Ching, 2)

I will interpret it in my own understanding. When people of the world all know beauty as beauty, there arises the recognition of ugliness. As I understood all of things have their opposite or if there is a thing that arises, there is something that you could recognize from it. It is harmful to know something because all of the things have their opposite side and one might not want the outcome or the negative side and he/she might be affected by it. When a person is beautiful outside, there may be a negative or ugliness in him/her somehow. One thing complements others and one thing negates others. When a thing has its strength, it will always have a weakness in it. When you want to know about the beauty of a thing, recognizing its ugliness is inevitable. When one pursue to know what really the thing is about, he/she might be disappointed to know the negative side of a thing, because he only pursue the good side of it and only to discover that it has its negative side.