CHAPTER XVIII.
In the preceding chapter has been determined how each Moral Virtue comes from one root, or first principle, that is, a good habit of choice; and the present text bears upon that, until the part which begins: "Nobility by right." In this part, then, it proceeds, by a way that is allowable, to teach that each Virtue mentioned above, taken singly, or otherwise generally, proceeds from Nobility as an effect from its cause, and it is founded upon a philosophical proposition, which says that, when two things are found to meet in one, both these things must be reduced to a third, or one to the other, as an effect to a cause: because one thing having stood first and of itself, it cannot exist except it be from one; and if those two could not be both the effect of a third, or else one the effect of the other, each would have had a separate first cause, which is impossible.

It says, then, that Such virtue shows its good To others' intellect, For when two things agree in one, Producing one effect, One must from other come, Or each one from a third, If each be as each, and more, then one From the other is inferred.
Where it is to be known that here one does not proceed by an evident demonstration; as it would be to say that the cold is the generative principle of water, when we see the clouds; but certainly by a beautiful and suitable induction.

For if there are many laudable things in us, and one is the principle or first cause of them all, reason requires each to be reduced to that first cause, which comprehends more things; and this ought more reasonably to be called the principle of those things than that which comprehends in itself less of their principle.

For as the trunk of a tree, which contains or encloses all the other branches, ought to be called the first beginning and cause of those branches, and not those branches the cause of the trunk, so Nobility, which comprehends each and every Virtue (as the cause contains the effect) and many other actions or operations of ours which are praiseworthy, it ought to be held for such; that the Virtue may be reduced to it, rather than to the other third which is in us.

Finally it says that the position taken (namely, that each Moral Virtue comes from one root, and that such Virtue and Nobility unite in one thing, as is stated above, and that therefore it is requisite to reduce the one to the other, or both to a third; and that if the one contains the value of the other and more, from that it proceeds rather than from the other third) may be considered as a rule established and set forth, as was before intended.
And thus ends this passage and this present part..