Natural, or innocent, anger is the necessary reaction of a creature when its survival is threatened by the attack of another creature and it cannot save itself (or its offspring) by flight. Such anger, accompanied by physiological changes, like increased secretion of adrenalin, inhibits fear so that the attacked creature is able to resist the threat to its extinction. In the case of young creatures that are not yet capable of looking after themselves, anger is a necessary emotion when their needs are neglected: a hungry baby does right to scream. Natural anger is a reflex reaction, not a voluntary one; it is a response to a real situation of threat and danger, and as soon as the threat is removed, the anger subsides. No animal lets the sun go down upon its wrath. Moreover, Lorentz has shown that, in fights between the social animals, when, by adopting a submissive posture, the weaker puts itself at the mercy of the stronger, this inhibits further aggression by the latter.
Anger, even when it is sinful, has one virtue; it overcomes sloth. Anybody, like a schoolmaster, a stage director or an orchestral conductor, whose business it is to teach others to do something, knows that, on occasions, the quickest – perhaps the only – way to get those under him to do their best is to make them angry.
Anger as a sin is either futile (the situation in which one finds oneself cannot or should not be changed, but must be accepted) or unnecessary (the situation could be mastered as well or better without it). Man is potentially capable of the sin of anger because he is endowed with memory – the experience of an event persists – and with the faculty of symbolization (to him, no object or event is simply itself). He becomes actually guilty of anger because he is first of all guilty of the sin of pride, of which anger is one of many possible manifestations.