He introduces his essay with the idea that philosophers have concentrated in ample measure on the rules of logic, but have not (especially since the time of Immanuel Kant) engaged with the darker art of the dialectic, of controversy.
In Volume 2, § 26, of his Parerga and Paralipomena, Schopenhauer wrote: The tricks, dodges, and chicanery, to which they [men] resort in order to be right in the end, are so numerous and manifold and yet recur so regularly that some years ago I made them the subject of my own reflection and directed my attention to their purely formal element after I had perceived that, however varied the subjects of discussion and the persons taking part therein, the same identical tricks and dodges always come back and were very easy to recognize.
This led me at the time to the idea of clearly separating the merely formal part of these tricks and dodges from the material and of displaying it, so to speak, as a neat anatomical specimen.
He "collected all the dishonest tricks so frequently occurring in argument and clearly presented each of them in its characteristic setting, illustrated by examples and given a name of its own."
As an additional service, Schopenhauer "added a means to be used against them, as a kind of guard against these thrusts..." However, when he later revised his book, he found "that such a detailed and minute consideration of the crooked ways and tricks that are used by common human nature to cover up its shortcomings is no longer suited to my temperament and so I lay it aside."