Good & evil are the grab of the let's say incarnational worlds ,
and are how our mind-heart-prana-part of our spirit.. is lead into the relatively artificial (constructed) nature of at least this uni-verse.
It seems like a good model , on the surfaces...... however, that system is based on the participating beings.... ecsisting under ecsperiencing & feeling that model, and it's a lila, so it's okay! Now we just use Yoga a bit to challenge the lila jus a bit.... play with the lila.... thou art the master , and may have fun peeking (thanks peekie 
)behind where source god sh i va narayana is also playing, giving birth to all of this.