the mind of Ethical agents, yet the sovereign authority that he proclaims is not Conscience or Sentiment, but Reason.  The subordination of Sentiment to Reason is with him essential.  It is true that Reason must be supplied with First Principles, whence to take its start; and these First Principles are here declared to be, fixed emotional states or dispositions, engendered in the mind of the agent by a succession of similar acts.  But even these dispositions themselves, though not belonging to the department of Reason, are not exempt from the challenge and scrutiny of Reason; while the proper application of them in act to the complicated realities of life, is the work of Reason altogether.  Such an ethical theory calls upon Aristotle to indicate, more or less fully, those intellectual excellences, whereby alone we are enabled to overcome the inherent difficulties of right ethical conduct; and he indicates them in the present Book, comparing them with those other intellectual excellences which guide our theoretical investigations, where conduct is not directly concerned.

In specifying the ethical excellences, or excellences of disposition, we explained that each of them aimed to realize a mean—­and that this mean was to be determined by Right Reason.  To find the mean, is thus an operation of the Intellect; and we have now to explain what the right performance of it is,—­or to enter upon the Excellences of the Intellect.  The soul having been divided into Irrational and Rational, the Rational must farther be divided into two parts,—­the Scientific (dealing with necessary matter), the Calculative, or Deliberative (dealing with contingent matter).  We must touch, upon the excellence or best condition of both of them (I).  There are three principal functions of the soul—­Sensation, Reason, and Appetite or Desire.  Now, Sensation (which beasts have as well as men) is not a principle of moral action.  The Reason regards truth and falsehood only; it does not move to action, it is not an end in itself.  Appetite or Desire, which aims at an end, introduces us to moral action.  Truth and Falsehood, as regards Reason, correspond to Good and Evil as regards Appetite:  Affirmation and Negation, with the first, are the analogues of Pursuit and Avoidance, with the second.  In purpose, which is the principle of moral action, there is included deliberation or calculation.  Reason and Appetite are thus combined:  Good Purpose comprises both true affirmation and right pursuit:  you may call it either an Intelligent Appetite, or an Appetitive Intelligence.  Such is man, as a principle of action [hae toiautae archae anthropos].

Science has to do with the necessary and the eternal; it is teachable, but teachable always from praecognita, or principles, obtained by induction; from which principles, conclusions are demonstrated by syllogism (III.).  Art, or Production, is to be carefully distinguished from the action or agency that belongs to man as an ethical agent, and that does not terminate in any separate assignable product.  But both the one and the other deal with contingent matters only.  Art deals for the most part with the same matters as are subject to the intervention of Fortune or Chance (IV.).