There are many technical rules and principles of logic which we cannot attempt to consider here. There are, however, a few elementary principles of correct reasoning which should have a place here. What is known as a "syllogism" is the expression in words of the various parts of the complete process of reasoning or argument. Whately defines it as follows: "A syllogism is an argument expressed in strict logical form so that its conclusiveness is manifest from the structure of the expression alone, without any regard to the meaning of the term." In short, _if_ the two premises are accepted as correct, it follows that there can be only one true logical conclusion resulting therefrom. In abstract or theoretical reasoning the word "_if_" is assumed to precede each of the two premises, the "therefore" before the conclusion resulting from the "if," of course. The following are the general rules governing the syllogism:-- I. Every syllogism must consist of three, and no more than three, propositions, namely (1) the major premise, (2) the minor premise, and (3) the conclusion. II. The conclusion must naturally follow from the premises, otherwise the syllogism is invalid and constitutes a fallacy or sophism. III. One premise, at least, must be affirmative. IV. If one premise is negative, the conclusion must be negative. V. One premise, at least, must be universal or general. VI. If one premise is particular, the conclusion also must be particular. The last two rules (V. and VI.) contain the essential principles of all the rules regarding syllogisms, and any syllogism which breaks them will be found also to break other rules, some of which are not stated here for the reason that they are too technical. These two rules may be tested by constructing syllogisms in violation of their principles. The reason for them is as follows: (Rule V.) Because "from two particular premises no conclusion can be drawn," as, for instance: (1) Some men are mortal; (2) John is a man. We cannot reason from this either that John _is_ or _is not_ mortal. The major premise should read "_all_ men." (Rule VI.) Because "a universal conclusion can be drawn only from two universal premises," an example being needless here, as the conclusion is so obvious. CULTIVATION OF REASONING FACULTIES.