“Human beings are accountable for their conduct; brutes, not being human, are therefore _free from responsibility_.” (Not accountable for their conduct.) “Not all educated men spell correctly; because one often finds mistakes in the writings of _college graduates_.” (Educated men.) “Modern education is not popular in this state; for it increases the tax rate, and the popularity of everything, which _touches the pocket_ of these frugal Yankees, (increases the tax rate) is very short lived.” (Not popular.) In common parlance the use of synonyms is so prevalent that ready ability to substitute equivalents in word, phrase, and clause form is needed by him who would be skillful in testing all kinds of arguments. It has already become apparent to the student that the _number_ of the noun or the _tense_ of the verb is of small logical consequence. A very large proportion of the formal fallacies in argumentation concern the rules of distribution which are summarized in the dictum “What may be said of the whole may be said of part of that whole.” =6. COMMON MISTAKES OF STUDENTS IN TESTING ARGUMENTS.= The most common mistakes made by the student when testing arguments are as follows: (1) Using the exclusive as an “A” without interchanging subject and predicate; e. g., interpreting the proposition, “Only high school graduates may enter the training school,” as meaning “All high school graduates may enter the training school.” (2) _Calling individual propositions particular_; e. g., interpreting “Socrates is mortal” as an “I” rather than an “A.” (3) Signifying that partitive propositions are “A’s” rather than “O’s”; e. g., “All that glitters is not gold” interpreted as meaning that “All glittering things are gold,” rather than “Some glittering things are not gold.” (A). (4) Concluding that a fallacy of four terms has been committed when two terms are synonomous. (5) Failing to interchange the subject and predicate of inverted propositions. =7. OUTLINE.= CATEGORICAL ARGUMENTS TESTED ACCORDING TO FORM. (1) Arguments of form and matter. (2) Order of procedure in the formal testing of arguments. The outline. Determining premises and conclusion. Completing abbreviated arguments. (3) Illustrative exercises in testing arguments which are complete and whose premises are logical. (4) Illustrative exercises in testing completed arguments, one or both of whose premises are illogical. Exclusive premises, individual premises, partitive premises, inverted premises. (5) Incomplete and irregular arguments. (6) Common mistakes of the student. =8. SUMMARY.= (1) In determining their validity, arguments must be tested from the two viewpoints of _form_ and _matter_. (2) In testing categorical arguments it is quite necessary to be definite, to give reasons, and to give the author the benefit of the doubt. With this in view the attending outline is suggestive: