Agression the eternal paradox

Can anyone justify aggression? Act of aggression or violence is always based on the idea of some future events. One can make reasonable justification when referring to something that will, can, or may happen. Now an interesting point is that all future events are always mental. They are never facts. An intelligent mind can foresee future events. Science makes great achievements. However those kind of events are never a base for aggression or violence because the models do not involve agents with intentional behaviour. When models do involve human players, the future events cease being facts. And said above justification becomes based on assumptions, strong or weak still assumptions, which are mere somebody's opinions.