A corroboration of what I have said is[30] the fact, that the young come to be geometricians, and mathematicians, and Scientific in such matters, but it is not thought that a young man can come to be possessed of Practical Wisdom: now the reason is, that this Wisdom has for its object particular facts, which come to be known from experience, which a young man has not because it is produced only by length of time. By the way, a person might also enquire,[31] why a boy may be made a mathematician but not Scientific or a natural philosopher. Is not this the reason? that mathematics are taken in by the process of abstraction, but the principles of Science[32] and natural philosophy must be gained by experiment; and the latter young men talk of but do not realise, while the nature of the former is plain and clear. Again, in matter of practice, error attaches either to the general rule, in the process of deliberation, or to the particular fact: for instance, this would be a general rule, “All water of a certain gravity is bad;” the particular fact, “this water is of that gravity.” And that Practical Wisdom is not Knowledge is plain, for it has to do with the ultimate issue,[33] as has been said, because every object of action is of this nature. To Intuition it is opposed, for this takes in those principles which cannot be proved by reasoning, while Practical Wisdom is concerned with the ultimate particular fact which cannot be realised by Knowledge but by Sense; I do not mean one of the five senses, but the same by which we take in the mathematical fact, that no rectilineal figure can be contained by less than three lines, i.e. that a triangle is the ultimate figure, because here also is a stopping point. This however is Sense rather than Practical Wisdom, which is of another kind.[34] Chapter IX. Now the acts of enquiring and deliberating differ, though deliberating is a kind of enquiring. We ought to ascertain about Good Counsel likewise what it is, whether a kind of Knowledge, or Opinion, or Happy Conjecture, or some other kind of faculty. Knowledge it obviously is not, because men do not enquire about what they know, and Good Counsel is a kind of deliberation, and the man who is deliberating is enquiring and calculating. Neither is it Happy Conjecture; because this is independent of reasoning, and a rapid operation; but men deliberate a long time, and it is a common saying that one should execute speedily what has been resolved upon in deliberation, but deliberate slowly. Quick perception of causes[35] again is a different faculty from good counsel, for it is a species of Happy Conjecture. Nor is Good Counsel Opinion of any kind.