1. A B C D P₁ 2. A D E F P₂ 3. A L M N P₃ 4. A O P Q P₄ 5. O P Q ― 6. L M N ― 7. D E F ― 8. B C D ― It is obvious that the first, second, third and fourth groups of instances illustrate the principle of Agreement; whereas the first and eighth, the second and seventh, the third and sixth, and the fourth and fifth illustrate in each case, the principle of Difference. (3) Concrete Examples illustrating Joint Method. _The problem_: Too much whispering. _Antecedents_ _Consequent_ 1. Insufficient work, } Lack of interest, } Much whispering. _Seated near a friend._ } 2. More work, } Lack of interest, } Much whispering. _Seated near a friend._ } 3. More work, } More interest, } Much whispering. _Seated near a friend._ } 4. More work, } More interest, } Not much whispering. _Not seated near a friend._ } 5. More work, } Lack of interest, } Not much whispering. _Not seated near a friend._ } 6. Insufficient work, } Lack of interest, } Not much whispering. _Not seated near a friend._ } From this it may be concluded that the undue amount of whispering is caused by seating particular friends near each other. _The problem_: Poor recitations. _Antecedents_ _Consequent_ 1. Long lesson, } Faulty assignment of lesson, } Poor recitation. _Fear of teacher._ } 2. Lesson made shorter, } Faulty assignment of lesson, } Poor recitation. _Fear of teacher._ } 3. Lesson made shorter, } A more careful assignment, } Poor recitation. _Fear of teacher._ } 4. Lesson made shorter, } A more careful assignment, } Good recitation. _Removal of fear of teacher._ } 5. Lesson made shorter, } Faulty assignment, } Good recitation. _No fear of teacher._ } 6. Lesson long, } Faulty assignment, } Good recitation. _No fear of teacher._ } Fear of teacher is the cause of the poor recitation. (4) Distinguishing features. Being a combination of Agreement and Difference the Joint Method possesses the characteristics of _each_, though more or less modified. The distinguishing marks may be summarized as follows: (1) Of the first group of instances: (1) The phenomenon must always occur, (2) One antecedent must be invariable, (3) The other antecedents must be more or less variable.