Aristotle, Nicomachean Ethics
H. Rackham, Ed.

[8] When an injury is done knowingly but not deliberately, it is （3） an act of injustice or wrong; such, for instance, are injuries done through anger, or any other unavoidable or natural passion to which men are liable; since in committing these injuries and errors a man acts unjustly, and his action is an act of injustice, but he is not ipso facto unjust or wicked, for the injury was not done out of wickedness. When however an injury is done from choice, the doer is unjust and wicked. [9] Hence acts due to sudden anger are rightly held not to be done of malice aforethought, for it is the man who gave the provocation that began it, not he who does the deed in a fit of passion. [10] And moreover the issue is not one of fact, but of justification （since it is apparent injustice that arouses anger）; the fact of the injury is not disputed （as it is in cases of contract, where one or the other of the parties must be a knave, unless they dispute the facts out of forgetfulness）. They agree as to the facts but dispute on which side justice lies so that one thinks he has been unjustly treated and the other does not. On the other hand, one who has planned an injury is not acting in ignorance;¹