; for all
things which are to be taken, or chosen, or desired, ought to exist in the
chief good, so that he who has attained that may want nothing more. Do you
not see how evident it is to those men whose chief good consists in
pleasure, what they ought to do and what they ought not? so that no one of
them doubts what all their duties ought to regard, what they ought to
pursue, or avoid. Let this, then, be the chief good which is now defended
by me; it will be evident in a moment what are the necessary duties and
actions. But you, who set before yourselves another end except what is
right and honourable, will not be able to find out where your principle of
duty and action is to originate.

Therefore you are all of you seeking for this, and so are those who say
that they pursue whatever comes into their mind and occurs to them; and
you return to nature. But nature will fairly reply to you, that it is not
true that the chief happiness of life is to be sought in another quarter,
but the principles of action in herself: for that there is one system
only, in which both the principles of action and the chief good too is
contained; and that, as the opinion of Aristo is exploded, when he says
that one thing does not differ from another, and that there is nothing
except virtue and vice in which there was any difference whatever; so,
too, Zeno was in the wrong, who affirmed that there was no influence in
anything, except virtue or vice, of the very least power to assist in the
attainment of the chief good: and as that had no influence on making life
happy, but only in creating a desire for things, he said that there was
some power of attraction in them: just as if this desire had no reference
to the acquisition of the chief good. But what can be less consistent than
what they say, namely, that when they have obtained the knowledge of the
chief good they then return to nature, in order to seek in it the
principle of action, that is to say, of duty? For it is not the principle
of action or duty which impels them to desire those things which are
according to nature; but desire and action are both set in motion by those
things.

XVIII. Now I come to those brief statements of yours which you call
conclusions; and first of all to that--than which, certainly, nothing can
be more brief--that "everything good is praiseworthy; but everything
praiseworthy is honourable; therefore everything good is honourable." Oh,
what a leaden dagger!--f