Since, then, we have now discussed what is honourable and what is useful, it remains for us to say a little of those things which we have said are attached to these other things; namely, affection and necessity.

LVII.  I think, then, that necessity means that which cannot be resisted by any power; that which cannot be softened nor altered.  And that this may be made more plain, let us examine into the meaning of it by the light of examples, so as to see what its character and how great its power is.  “It is necessary that anything made of wood must be capable of being burnt with fire.  It is necessary that a mortal body should at some time or other die.”  And it is so necessary, that that power of necessity which we were just now describing requires it; which cannot by any force whatever be either resisted, or weakened, or altered.  Necessities of this kind, when they occur in oratory, are properly called necessities; but if any difficult circumstances arise, then we shall consider in the previous examination whether it, the thing in question, be possible to be done.  And it seems to me, that I perceive that there are some kinds of necessity which admit of additions, and some which are simple and perfect in themselves.  For we say in very different senses:—­“It is necessary for the people of Casilinum to surrender themselves to Hannibal;” and, “It is necessary that Casilinum should come into the power of Hannibal.”  In the one case, that is, in the first case, there is this addition to the proposition:—­“Unless they prefer perishing by hunger.”  For if they prefer that, then it is not necessary for them to surrender.  But in the latter proposition such an addition has no place; because whether the people of Casilinum choose to surrender, or prefer enduring hunger and perishing in that manner, still it is necessary that Casilinum must come into the power of Hannibal.  What then can be effected by this division of necessity?  I might almost say, a great deal, when the topic of necessity appears such as may be easily introduced.  For when the necessity is a simple one, there will be no reason for our making long speeches, as we shall not be able by any means to weaken it; but when a thing is only necessary provided we wish to avoid or to obtain something, then it will be necessary to state what advantage or what honour is contained in that addition.  For if you will take notice, while inquiring what this contributes to the advantage of the state, you will find that there is nothing which it is necessary to do, except for the sake of some cause which we call the adjunct.  And, in like manner, you will find that there are many circumstances of necessity to which a similar addition cannot be made; of such sort are these:—­“It is necessary that mortal men should die;” without any addition:—­“It is not necessary for men to take food;” with this exception,—­“Unless they have an objection to dying of hunger.”