For the Principles of the matters of moral action are the final cause of them:[19] now to the man who has been corrupted by reason of pleasure or pain the Principle immediately becomes obscured, nor does he see that it is his duty to choose and act in each instance with a view to this final cause and by reason of it: for viciousness has a tendency to destroy the moral Principle: and so Practical Wisdom must be “a state conjoined with reason, true, having human good for its object, and apt to do.” Then again Art admits of degrees of excellence, but Practical Wisdom does not:[20] and in Art he who goes wrong purposely is preferable to him who does so unwittingly,[21] but not so in respect of Practical Wisdom or the other Virtues. It plainly is then an Excellence of a certain kind, and not an Art. Now as there are two parts of the Soul which have Reason, it must be the Excellence of the Opinionative [which we called before calculative or deliberative], because both Opinion and Practical Wisdom are exercised upon Contingent matter. And further, it is not simply a state conjoined with Reason, as is proved by the fact that such a state may be forgotten and so lost while Practical Wisdom cannot. Chapter VI. Now Knowledge is a conception concerning universals and Necessary matter, and there are of course certain First Principles in all trains of demonstrative reasoning (that is of all Knowledge because this is connected with reasoning): that faculty, then, which takes in the first principles of that which comes under the range of Knowledge, cannot be either Knowledge, or Art, or Practical Wisdom: not Knowledge, because what is the object of Knowledge must be derived from demonstrative reasoning; not either of the other two, because they are exercised upon Contingent matter only. Nor can it be Science which takes in these, because the Scientific Man must in some cases depend on demonstrative Reasoning. It comes then to this: since the faculties whereby we always attain truth and are never deceived when dealing with matter Necessary or even Contingent are Knowledge, Practical Wisdom, Science, and Intuition, and the faculty which takes in First Principles cannot be any of the three first; the last, namely Intuition, must be it which performs this function. Chapter VII. Science is a term we use principally in two meanings: in the first place, in the Arts we ascribe it to those who carry their arts to the highest accuracy;[22] Phidias, for instance, we call a Scientific or cunning sculptor; Polycleitus a Scientific or cunning statuary; meaning, in this instance, nothing else by Science than an excellence of art: in the other sense, we think some to be Scientific in a general way, not in any particular line or in any particular thing, just as Homer says of a man in his Margites; “Him the Gods made neither a digger of the ground, nor ploughman, nor in any other way Scientific.”