A brief course in the teaching process

by George D. Strayer

CHAPTER VI
THE DEDUCTIVE LESSON

The complete process of thought involves both induction and deduction. Every general principle, unless it is self-evident, must either be arrived at through the process of induction, or be accepted without any attempt at verification. Having formed our generalizations, we use them as a basis for further thinking. If we find that the principle always holds, we are satisfied with its validity. In this testing of the generalization tentatively made, the process of thought is deductive. The fact is that in the process which we designate as induction, deduction enters to verify our inference. In the face of the problem which can be settled only by reference to some established principle, we find ourselves questioning the generalizations formerly accepted, and the process of thought in solving our problem will involve induction as well as deduction. For convenience we treat the problems of teaching under the two heads, the inductive and the deductive lesson, according as one or the other type of thought seems to predominate in reasoning required to solve the problem involved.

Every one thinks deductively who has had sufficient experience to form any generalizations. In the early life of the child we find the psychological basis for deduction in the tendency to act in accordance with ideas. Children define things in terms of their function. Thus a hat is something to wear on the head; a drawer something to pull out and push in; a shovel something to move the sand with; and so for the other objects in the child world. A child makes a dog in clay, draws a picture of a flower, makes a house of his blocks—and in this way tests his ideas. Not all deductive thinking ends in motor activity; but we can never be satisfied with our deductions until we have established them experimentally. The question concerning our ideas always is, will they work?

Whenever we offer an explanation of our ideas or of our actions, the process of thought is deductive. Not that either adults or children often state the general principle upon which they base their statement or action. We are all only too prone to assume the general principle. The foolish answers which children give may be logical enough. From his very limited experience a boy may have generalized that grass is something to look at and not to be walked on, and that people always live in houses from four to ten stories high, with many families in a house. Now, if such erroneous generalizations have been developed, the way to handle the boy is not to laugh at his deductions from these premises, but rather to require him to state the generalizations upon which he has based his thinking, and to lead him to discover their inadequacy. It matters not what group of children one works with, this same need for a declaration of the principle upon which the argument is based, the generalization which covers the situation under consideration, will be found essential. That teacher does much for the children who frequently pushes them back to a statement of what they assume to be true. This statement is not always easy to make. Even with adults it is very common to explain action by reference to some feeling or attitude which it is assumed has some basis in reason. Some instinctive tendency, or a mode of feeling, thinking, or acting which has become habitual, frequently explains, but fails to justify our actions. The ability to state clearly what one assumes, and to claim as valid only such conclusions as are based on premises which are admitted to be true, is the mark of the man of unusual rationality.

There is no set of rules which a teacher may follow in order to make the children she teaches logically minded. On the other hand, all of her activity tends in some degree to encourage or to eliminate the logical habit of mind. The teacher who dogmatizes continually in her teaching can do little to overcome a like tendency in the children by conducting exercises logically correct. The wrong emphasis on correctness of the result, instead of correctness of the method employed in getting the result, encourages much illogical work and develops careless habits of thought. And it is just as true that an open-minded attitude on the part of the teacher will be reflected in the children. The teacher who insists upon the verification of generalizations, who asks children frequently to give the ground for the statements which they make, and who encourages reflection, will engender logical habits of thought.

To recognize the wide application of the deductive method in our thinking, one has only to consider what is meant by reflection. It is well also in this connection to remember that the habit of reflection distinguishes the educated from the uneducated man. It is not the number of experiences which makes the difference between men, but rather the use that has been made of those experiences. When we reflect, we think over, organize, and relate our past experiences. Suppose, for example, that some one makes the statement that corporal punishment should be banished from all schools. If you reflect upon such a thesis, you bring to bear your experiences, whether of action, observation, or thought stimulated by reading what some one else has said; and, as a result of your thinking, you consciously or unconsciously assume a general principle under which you feel satisfied that this question of discipline falls; and then you will refer all of your experiences to this principle, testing its validity by seeing whether or not it does uniformly hold. The process of thinking which you have employed is essentially deductive. If stated in the form of a syllogism, it might be expressed somewhat as follows:—

1. Any action which tends to brutalize either pupil or teacher should not be permitted in any school.

2. Corporal punishment tends to brutalize both teacher and pupil.

3. Hence corporal punishment should be banished from all schools.