Aristotle, Nicomachean Ethics
H. Rackham, Ed.

3. [8] Also there is no room for deliberation about matters fully ascertained and completely formulated as sciences; such for instance as orthography, for we have no uncertainty as to how a word ought to be spelt. We deliberate about things in which our agency operates, but does not always produce uniform results; for instance about questions of medicine and of business; and we deliberate about navigation more than about athletic training, because it has been less completely reduced to a science; and similarly with other pursuits also. 3. [9] And we deliberate more about the arts¹ than about the sciences, because we are more uncertain about them.3. [10]

Deliberation then is employed in matters which, though subject to rules that generally hold good, are uncertain in their issue; or where the issue is indeterminate,² and where, when the matter is important, we take others into our deliberations, distrusting our own capacity to decide.3. [11]

And we deliberate not about ends, but about means. A doctor does not deliberate whether he is to cure his patient, nor an orator whether he is to convince his audience, nor a statesman whether he is to secure good government, nor does anyone else debate about the end of his profession or calling; they take some end for granted, and consider how and by what means it can be achieved. If they find that there are several means of achieving it, they proceed to consider which of these will attain it most easily and best. If there is only one means by which it can be accomplished, they ask how it is to be accomplished by that means, and by what means that means can itself be achieved, until they reach the first link in the chain of causes, which is the last in the order of discovery.