The sixth set contains, a treatise against those who believe Truth and Falsehood to be the same thing. One, in two books, against those who have recourse to division to resolve the Fallacy, addressed to Aristocreon; a demonstrative essay, to prove that it is not proper to divide indefinite terms; an essay, in three books, in answer to the objections against the non-division of Indefinite Terms, addressed to Pasylus; a solution, according to the principles of the ancients, addressed to Dioscorides; an essay on the Resolution of the Fallacy, addressed to Aristocreon, this is in three books; a resolution of the Hypothetical Arguments of Hedylus, in one book, addressed to Aristocreon and Apollos. The seventh set contains, a treatise against those who contend that the premisses on the Fallacy, are false; a treatise on Negative Reasoning, addressed to Aristocreon, in two books; one book of Negative Reasonings, addressed to Gymnasias; two books of a treatise on Reasoning by Progression, addressed to Stesagoras; two books of Reasonings by Interrogation, and on the Arrest,[105] addressed to Onetor; an essay, in two books, on the Corrected Argument, addressed to Aristobulus; another on the Non-apparent Argument, addressed to Athenades. The eighth set contains, an essay on the Argument Outis, in eight books, addressed to Menecrates; a treatise, in two books, on Arguments composed of a finite term, and an indefinite term, addressed to Pasylus; another essay on the Argument Outis, addressed to Epicrates. The ninth set contains, two volumes of Sophisms, addressed to Heraclides, and Pollis; five volumes of Dialectic Arguments, which admit of no solution, addressed to Dioscorides; an essay, in one book, against the Method of Arcesilaus, addressed to Sphærus. The tenth set contains, a treatise in six books, against Custom, addressed to Metrodorus; and another, in seven books, on Custom, addressed to Gorgippides. There are, therefore, works on Logic, in the four grand classes which we have here enumerated, embracing various questions, without any connection with one another, to the number of thirty nine sets, amounting in the whole to three hundred and eleven treatises on Logic. The next division comprises those works which have for their object, the explanation of Moral Ideas. The first class of this division, contains an essay, giving a description of Reason, addressed to Theosphorus; a book of Ethical questions; three books of Principles, to serve as the foundation of Dogmas, addressed to Philomathes; two books of definitions of Good-breeding, addressed to Metrodorus; two books of definitions of the Bad, addressed to Metrodorus; two books of definitions of Neutral Things, addressed also to Metrodorus; seven books of definitions of Things, according to their genera, addressed to Metrodorus; and two books of Definitions, according to other systems, addressed to Metrodorus.