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.
Aristotle settles the point by distinguishing, in this case as in others, between what bears a given character simply and absolutely, and what bears the same character relatively to this or that individual.