Yin-Yang
Do you believe that everything is based upon the principles of 'Yin-Yang'?
Yin-Yang: in Chinese philosophy, the two cosmic forces of creative energy, yin being feminine/negative and yang being masculine/positive, from which everything originates and depends on the interaction of the opposite and complementary principles
Ref. Dictionary.com
The principles of Yin and Yang go beyond that. They represent that there is a little good in everything that is bad and a little bad in everything that is good. This is a hard philosophy for westerners to grasp because western religions have the principle of an all good force and an all bad force. Yin-Yang says that the lines are not so easily defined as all good and all evil.
I do believe that there is a certain balance to the world. And to be sure, I have found that most good things have something negative in them and most bad things, a little good can be found in it. So the principles them self are indeed self evident, but I rather think that the principle that something keeps it all in balance was an easy way to bend a religion around what one can see with their own eyes.