Next, anger has no value by itself. It doesn't stir the mind to brave acts in war. Virtue is complete on its own — it never needs help from a vice. When virtue needs fierce effort, it doesn't get angry. Instead, it rises to the challenge and excites or calms itself as much as needed. Think of war machines that shoot arrows — the operator can tighten or loosen them as he pleases.
"Anger is necessary," Aristotle says. "No battle can be won without it, unless it fills the mind and fires up the spirit. But anger should be used as a soldier, not as a general."
This is wrong. If anger listens to reason and follows where reason leads, it's no longer anger. Anger's main feature is stubbornness. But if anger won't listen and refuses to be quiet when ordered — if it gets carried away by its own willful spirit — then it's as useless to the mind as a soldier who ignores the retreat signal would be to his general.
In the next place, anger has nothing useful in itself, and does not rouse up the mind to warlike deeds: for a virtue, being self-sufficient, never needs the assistance of a vice: whenever it needs an impetuous effort, it does not become angry, but rises to the occasion, and excites or soothes itself as far as it deems requisite, just as the machines which hurl darts may be twisted to a greater or lesser degree of tension at the manager’s pleasure. “Anger,” says Aristotle, “is necessary, nor can any fight be won without it, unless it fills the mind, and kindles up the spirit. It must, however, be made use of, not as a general, but as a soldier,” Now this is untrue; for if it listens to reason and follows whither reason leads, it is no longer anger, whose characteristic is obstinacy: if, again, it is disobedient and will not be quiet when ordered, but is carried away by its own wilful and headstrong spirit, it is then as useless an aid to the mind as a soldier who disregards the sounding of the retreat would be to a general.