Eloquence is the faculty of stirring up in others our view of a thing, or our opinion regarding it, of kindling in them our feeling about it, and thus of putting them in sympathy with us; and all of this by our conducting the stream of our ideas into their heads by means of words, with such force that this stream diverts that of their own thoughts from the course already taken, and carries this away with it along its course.
[...] In order to convince another of a truth that conflicts with an error he holds firmly, the first rule to be observed is an easy and natural one, namely: Let the premisses come first, and the conclusion follow.
This rule, however, is seldom observed, and people go to work the reverse way, since zeal, hastiness, and dogmatic positiveness urge us to shout out the conclusion loudly and noisily at the person who adheres to the opposite error.
This easily makes him shy and reserved, and he then sets his will against all arguments and premisses, knowing already to what conclusion they lead. Therefore we should rather keep the conclusion wholly concealed and give only the premisses distinctly, completely, and from every point of view.
If possible, we should not even express the conclusion at all. It will appear of its own accord necessarily and legitimately in the reason of the hearers, and the conviction thus born within them will be all the more sincere; in addition, it will be accompanied by self-esteem instead of by a feeling of shame.
[...] In defending a thing, many people make the mistake of confidently advancing everything imaginable that can be said in its favour, and of mixing up what is true , half true, and merely plausible.
But the false is soon recognized, or at any rate felt, and then casts suspicion even on the cogent and true that is advanced along with it.
Therefore let us give the cogent and true pure and alone, and guard against defending a truth with grounds and arguments that are inadequate, and are thus sophistical, in so far as they are set up as adequate. For the opponent upsets these, and thus gains the appearance of having upset also the truth itself that is supported by them; in other words he brings forward argumenta ad hominem as argumenta ad rem.
The World as Will and Representation, Volume II, p.119
Battles and Challenges