The best method of cultivating the power of Judgment is the exercise of the faculty in the direction of making comparisons, of weighing differences and resemblances, and in generally training the mind along the lines of Logical Thinking. Another volume of this series is devoted to the latter subject, and should aid the student who wishes to cultivate the habit of logical and scientific thought. The study of mathematics is calculated to develop the faculty of Judgment, because it necessitates the use of the powers of comparison and decision. Mental arithmetic, especially, will tend to strengthen, and exercise this faculty of the mind. Geometry and Logic will give the very best exercise along these lines to those who care to devote the time, attention and work to the task. Games, such as chess, and checkers or draughts, tend to develop the powers of Judgment. The study of the definitions of words in a good dictionary will also tend to give excellent exercise along the same lines. The exercises given in this book for the cultivation and development of the several faculties, will tend to develop this particular faculty in a general way, for the exercise of Judgment is required at each step of the way, and in each exercise. Brooks says: "It should be one of the leading objects of the culture of young people to lead them to acquire the habit of forming judgments. They should not only be led to see things, but to have opinions about things. They should be trained to see things in their relations, and to put these relations into definite propositions. Their ideas of objects should be worked up into thoughts concerning the objects. Those methods of teaching are best which tend to excite a thoughtful habit of mind that notices the similitudes and diversities of objects, and endeavors to read the thoughts which they embody and of which they are the symbols." The exercises given at the close of the next chapter, entitled "Derived Judgments," will give to the mind a decided trend in the direction of logical judgment. We heartily recommend them to the student. The student will find that he will tend to acquire the habit of clear logical comparison and judgment, if he will memorize and apply in his thinking the following excellent _Primary Rules of Thought_, stated by Jevons: "I. _Law of Identity_: The same quality or thing is _always_ the same quality or thing, no matter how different the conditions in which it occurs. "II. _Law of Contradiction_: Nothing can at the same time and place _both_ be and not be. "III. _Law of Excluded Middle_: Everything must _either_ be, or not be; there is no other alternative or middle course." Jevons says of these laws: "Students are seldom able to see at first their full meaning and importance. All arguments may be explained when these self-evident laws are granted; and it is not too much to say that _the whole of logic will be plain to those who will constantly use these laws as their key_." CHAPTER XII.