Book VI appears to have in view two aims: (1) to describe goodness of intellect and discover its highest form or forms; (2) to show how this is related to goodness of character, and so to conduct generally. As all thinking is either theoretical or practical, goodness of intellect has _two_ supreme forms—Theoretical and Practical Wisdom. The first, which apprehends the eternal laws of the universe, has no direct relation to human conduct: the second is identical with that master science of human life of which the whole treatise, consisting of the _Ethics_ and the _Politics_, is an exposition. It is this science which supplies the right rules of conduct Taking them as they emerge in and from practical experience, it formulates them more precisely and organises them into a system where they are all seen to converge upon happiness. The mode in which such knowledge manifests itself is in the power to show that such and such rules of action follow from the very nature of the end or good for man. It presupposes and starts from a clear conception of the end and the wish for it as conceived, and it proceeds by a deduction which is dehberation writ large. In the man of practical wisdom this process has reached its perfect result, and the code of right rules is apprehended as a system with a single principle and so as something wholly rational or reasonable He has not on each occasion to seek and find the right rule applicable to the situation, he produces it at once from within himself, and can at need justify it by exhibiting its rationale, _i.e._ , its connection with the end. This is the consummate form of reason applied to conduct, but there are minor forms of it, less independent or original, but nevertheless of great value, such as the power to think out the proper cause of policy in novel circumstances or the power to see the proper line of treatment to follow in a court of law.