To make your opponent accept a proposition, you must give him the
counter-proposition as well, leaving him his choice of the two; and
you must render the contrast as glaring as you can, so that to avoid
being paradoxical he will accept the proposition, which is thus made
to look quite probable. For instance, if you want to make him admit
that a boy must do everything that his father tells him to do, ask him
"whether in all things we must obey or disobey our parents." Or, if
a thing is said to occur "often," ask whether by "often" you are to
understand few or many cases; and he will say "many." It is as though
you were to put grey next black, and call it white; or next white, and
call it black.