Formulate one reason why the discovery of nuclear capabilities has been good for mankind and one reason why that discovery has not been good for mankind.

Bad - Weapons of mass destruction

Good - They can be used to prevent direct conflict. Think of the relations between the U. S. and Russia; they aren't great, but both countries want to avoid war because both are equipped with Nuclear weapons. No one wins in nuclear warfare. Knowing this both countries are relying on diplomacy rather than war.