Ignorance of a general rule is matter for censure; ignorance of particular circumstances may be excused. [This became the famous maxim of law,—­’Ignorantia facti excusat, ignorantia juris non excusat.’] If the agent, when better informed, repents of his act committed in ignorance, he affords good proof that the act done was really involuntary.  Acts done from anger or desire (which are in the agent’s self) are not to be held as involuntary. (1) If they were, the actions of brutes and children would be involuntary. (2) Some of these acts are morally good and approved. (3) Obligation often attaches to these feelings. (4) What is done from desire is pleasant; the involuntary is painful. (5) Errors of passion are to be eschewed, no less than those of reason (I.).

The next point is the nature of Purpose, Determination, or Deliberate Preference [Greek:  proairesis], which is in the closest kindred with moral excellence, and is even more essential, in the ethical estimate, than acts themselves.  This is a part of the Voluntary; but not co-extensive therewith.  For it excludes sudden and unpremeditated acts; and is not shared by irrational beings.  It is distinct from desire, from anger, from wish, and from opinion; with all which it is sometimes confounded.  Desire is often opposed to it; the incontinent man acts upon his desires, but without any purpose, or even against his purpose; the continent man acts upon his purpose, but against his desires.  Purpose is still more distinct from anger, and is even distinct (though in a less degree) from wish [Greek:  boulaesis], which is choice of the End, while Purpose is of the Means; moreover, we sometimes wish for impossibilities, known as such, but we never purpose them.  Nor is purpose identical with opinion [Greek:  doxa], which relates to truth and falsehood, not to virtue and vice.  It is among our voluntary proceedings, and includes intelligence; but is it identical with predeliberated action and its results? (II.)

To answer this query, Aristotle analyzes the process of Deliberation, as to its scope, and its mode of operation.  We exclude from deliberation things Eternal, like the Kosmos, or the incommensurability of the side and the diagonal of a square; also things mutable, that are regulated by necessity, by nature, or by chance; things out of our power; also final ends of action, for we deliberate only about the means to ends.  The deliberative process is compared to the investigation of a geometrical problem.  We assume the end, and enquire by what means it can be produced; then again, what will produce the means, until we at last reach something that we ourselves can command.  If, after such deliberation, we see our way to execution, we form a Purpose, or Deliberate Preference [Greek:  proairesis].  Purpose is then definable as a deliberative appetency of things in our power (III.).

Next is started the important question as to the choice of the final End.  Deliberation and Purpose respect means; our Wish respects the End—­but what is the End that we wish?  Two opinions are noticed; according to one (Plato) we are moved to the good; according to the other, to the apparent good.  Both opinions are unsatisfactory; the one would make out an incorrect choice to be no choice at all; the other would take away all constancy from ends.