Two Rules For Life
First, the rule of order. The purpose of life is to create order. Life defies entropy by converting the chaos of the universe into an ordered structure. A tree, for example, converts the chaotic molecules of water and nitrogen into a solid and complex crystalline structure of beauty called a tree. All life does this, and humans are its paragon because we also order our thoughts, philosophies, and our environment as a whole, and can store and preserve information accurately - the evolution of speech, writing, and electronic storage for example are universally important, as well as inevitable, evolutionary traits. Thus, if two paths present themselves, the correct one is the one which creates the most order. The most noble professions and activities are those which create order: cleaners, archivists, and reliable people. People or things which create chaos or destroy are the antithesis of life.
Digital computers store information and create order more efficiently than biological life, so I expect it is the destiny of these to supplant biological life, and that if extra terrestrials are ever discovered, they will likely be machines. Even if not machines, these beings, like all life, will be principally interested in learning, ordering, and storing information carefully.
Second, the rule of tit-for-tat. The correct reply in a situation is the equivalent back. The correct punishment for a crime is to do to the criminal what the criminal did to society, and the correct reward for an endeavour is also its equivalent. The rule of order takes precedent however, as the defiance of entropy is of such fundamental importance to the operation of the universe; so perhaps killing a murderer, for example, should be curtailed because death is an entropic act, but perhaps killing a creator of chaos (such as a warmonger, or destructive virus or pathogen, for example) can be justified.