For this it is which has laid down laws concerning things just and unjust, and things honorable and base; and if it were not for these ordinances we should not be able to live with one another. It is by this also that we confute the bad and extol the good. Through this we educate the ignorant and appraise the wise; for the power to speak well is taken as the surest index of a sound understanding, and discourse which is true and lawful and just is the outward image of a good and faithful soul.
With this faculty we both contend against others on matters which are open to dispute and seek light for ourselves on things which are unknown; for the same arguments which we use in persuading others when we speak in public, we employ also when we deliberate in our own thoughts; and, while we call eloquent those who are able to speak before a crowd, we regard as sage those who most skilfully debate their problems in their own minds.
And, if there is need to speak in brief summary of this power, we shall find that none of
the things which are done with intelligence take place without the help of speech, but
that in all our actions as well as in all our thoughts speech is our guide, and is most
employed by those who have the most wisdom.