XX.

When you have elicited all your premisses, and your opponent has
admitted them, you must refrain from asking him for the conclusion,
but draw it at once for yourself; nay, even though one or other of the
premisses should be lacking, you may take it as though it too had been
admitted, and draw the conclusion. This trick is an application of the
fallacy _non causae ut causae_.


XXI.

When your opponent uses a merely superficial or sophistical argument
and you see through it, you can, it is true, refute it by setting
forth its captious and superficial character; but it is better to
meet him with a counter-argument which is just as superficial and
sophistical, and so dispose of him; for it is with victory that you
are concerned, and not with truth. If, for example, he adopts an
_argumentum ad hominem_, it is sufficient to take the force out of it
by a counter _argumentum ad hominem_ or _argumentum ex concessis_;
and, in general, instead of setting forth the true state of the case
at equal length, it is shorter to take this course if it lies open to
you.


XXII.

If your opponent requires you to admit something from which the