i've always thought of evil as a necessary counter to goodness. sort of like light and darkness...not to sound like a cliche, but light is matter, i think...or rather energy. regardless whatever it is, it is. which means that darkness must exist too, if only in idea. since darkness is defined as the absence of light...to have one means you must have the other. good and evil are the same way. i'm already talking too much, but bear with me. imagine creation without the fall of man. in the wide angle view i mean. sure it's great, it's beautiful, it's beyond words...but enter free will and knowledge of good and evil. suddenly through this tragic event, there is now an opportunity for the creator to make a sacrifice and show the world His love and His greatness. How much more glorious is creation now that the fall of man has made way for the great redemption? i'd say good and evil are not arbitrary, but a necessary part of the mind of God and...in fact...another mode of glory for Him....by the way... i kinda think the angels do have free will. though i imagine it's more difficult to convince yourself to rebel against God when you're in heaven. satan still managed though...isn't the odd that even satan is suceptible to satan's lies?