If you observe that your opponent designedly returns a negative answer to the questions which, for the sake of your proposition, you want him to answer in the affirmative, you must ask the converse of the proposition, as though it were that which you were anxious to see affirmed; or, at any rate, you may give him his choice of both, so that he may not perceive which of them you are asking him to affirm.

If you make an induction, and your opponent grants you the particular cases by which it is to be supported, you must refrain from asking him if he also admits the general truth which issues from the particulars, but introduce it afterwards as a settled and admitted fact; for, in the meanwhile, he will himself come to believe that he has admitted it, and the same impression will be received by the audience, because they will remember the many questions as to the particulars, and suppose that they must, of course, have attained their end.

The Essays of Arthur Schopenhauer; The Art of Controversy — Part 17

If the conversation turns upon some general conception which has no particular name, but requires some figurative or metaphorical designation, you must begin by choosing a metaphor that is favourable to your proposition. For instance, the names used to denote the two political parties in Spain, _Serviles_ and _Liberates_, are obviously chosen by the latter. The name _Protestants_ is chosen by themselves, and also the name _Evangelicals_; but the Catholics call them _heretics_. Similarly, in regard to the names of things which admit of a more exact and definite meaning: for example, if your opponent proposes an _alteration_, you can call it an _innovation_, as this is an invidious word. If you yourself make the proposal, it will be the converse. In the first case, you can call the antagonistic principle "the existing order," in the second, "antiquated prejudice." What an impartial man with no further purpose to serve would call "public worship" or a "system of religion," is described by an adherent as "piety," "godliness": and by an opponent as "bigotry," "superstition." This is, at bottom, a subtle _petitio principii_. What is sought to be proved is, first of all, inserted in the definition, whence it is then taken by mere analysis. What one man calls "placing in safe custody," another calls "throwing into prison." A speaker often betrays his purpose beforehand by the names which he gives to things. One man talks of "the clergy"; another, of "the priests."

The Essays of Arthur Schopenhauer; The Art of Controversy — Part 17