_Chief Value of the Syllogism._--The chief use of the syllogism, I apprehend, however, to be, not in presenting a train of argument for the purpose of convincing and persuading others; for the laws of thought do not require us in such a case to state every thing that is even essential to the argument, but only so much as shall clearly indicate our meaning, and enable the hearer or reader to follow us; but rather in testing the soundness or detecting the unsoundness of an argument, whether our own, or that of an opponent. For this purpose, an acquaintance with the forms and laws of syllogism may be of great service to the writer and to the orator. _Objection to the Syllogism._--But it is objected to the syllogism that it is of no value in the discovery and establishment of truth, inasmuch as, by the very laws of the syllogism, there can be nothing more in the conclusion than was assumed in the premises. There is, and can be, in this way, no progress from the known to the unknown. The very construction of the syllogism, it is said, involves a _petitio principii_. When I say, All men are mortal; Socrates is a man; therefore, Socrates is mortal; the major premiss, it is said, affirms the very thing to be proved; that Socrates is mortal is virtually affirmed in the proposition that _all_ men are so. Either, then, the syllogism proves nothing which was not known before, or else the general proposition, with which it sets out, is unwarranted, as asserting more than we know to be true, and, in that case, the conclusion is equally unreliable; in either case nothing is gained by the process; the syllogism is worthless. _Lies equally against all reasoning._--This objection, if valid against the syllogism, is valid against and overthrows not the syllogism merely, but all reasoning of whatever kind, and in whatever form. It is an objection which really applies, not to the form which an argument may happen to assume, but to the essential nature of reasoning itself. As was shown in discussing the nature of the reasoning process, all reasoning is, in its nature, essentially analytic. It is the evolution of a truth that lies involved in some already admitted truth. It simply develops, draws out, what was therein contained. Its starting-point must always be some admitted position, its conclusions must always be some inevitable necessary consequence of that admission. The mortality of Socrates is, indeed, involved and contained in the general proposition which affirms the mortality of all men, and so, also, is every inferred truth contained in that from which it is inferred.