Tao Te Ching Chapter 2

When the world knows beauty as beauty, ugliness arises
When it knows good as good, evil arises
Thus being and nonbeing produce each other
Difficult and easy bring about each other(1)

Long and short reveal each other
High and low support each other
Music and voice harmonize each other
Front and back follow each other(2)
Therefore the sages:
Manage the work of detached actions
Conduct the teaching of no words
They work with myriad things but do not control
They create but do not possess
They act but do not presume
They succeed but do not dwell on success
It is because they do not dwell on success
That it never goes away


Translation and Annotation by Derek Lin


(1) Tao sages have long recognized the relative nature of the world. Values have meaning only in comparison. For instance, a task can only be "easy" if we compare it to some other task that is more difficult. If there is nothing else to compare it with, the task cannot be rated in terms of difficulty.
(2) Similarly, we can only say an object is "long" if we are comparing it to another similar object that is shorter. Each half of a duality cannot exist without the other. A descriptive concept creates its own opposite. This relative concept applies to everything, even good and evil.
What about absolute good and evil? Do they exist in the Tao? While we can certainly find absolutes in abstract theory, in the real world they rarely, if ever, exist. For instance, no metal is absolutely free of impurities. In fact, hardly anything in nature is absolutely pure. We can get close to 100 per cent but never quite reach that absolute state.
It is the same with people. Absolute good and evil can exist as concepts, but we will never find them in human beings. We are all mixtures of varying proportions. None of us is any one thing.