A teacher must have the tools to teach, therefore he needs to have a mastery of the subject matter. He also needs to know educational methods and educational principles. These are the tools that are necessary plus he must have a knowledge of the mental activity of the student. A person who teaches has to know how the student learns in order to use the knowledge he has to have the student learn, he has to choose a method of teaching. A teacher always needs a method of teaching. When he teaches he has to be sure his thoughts are reaching the student and needs to encourage and stimulate the student to learn.
When a child is born there is so much potential as he knows nothing and is unable to do much. If his brain is normal he has the mechanisms for learning. Of those mechanisms of the brain there are receptors that are the end-organs of the senses that receive stimulation. There are also effectors, the muscles that receive and use the current sent from conductions called nerves, or neurones, that carry the nerve impulses from place to place. Nerve impulses aroused by the reception of stimuli are carried from the receptors, which are located in all parts of the body, to the central system, which includes the brain, the mid-brain, and the spinal cord.
There are three levels of action an impulse will take in its passage from neurone to neurone through the central system depending upon the resistance offered at the synapse. These pathways might be grouped in three levels. There is a reflex level and in this level the degree of relationship is so close that a given impulse brought in over a certain neurone to a specific end-brush always goes to the same dendrite, the result is reaction on this lowest level. In this, connections in the spinal cord are used. The second level is called instinctive reaction, a type of action resulting from the relationship at the synapse being not so close or simple, yet enough so that the general character of the automatic reactions will be the same. The third level of reaction is the level of acquired connections. Reactions on this level are usually less prompt, and easier to modify.
The three levels of action are what concerns a teacher as learning is a matter of getting connections to the nervous system, particularly the brain, into such a close degree of relationship that the impulse from a desired stimulus will take a desired course across the synapse and produce the desired reaction. As a teacher he would be choosing the correct stimli, guiding activity and producing strength in connections, or bonds, that will result in certain definite reactions.
There is also conscious response, which includes being conscious as consciousness is a part of the response, something beyond the physical and material present. Knowledge can exist only in a person's mind. There is a transformation that takes place as myriads of sensations come from the receptors to the brain that makes these things of the mind. They pass from the realm of the physical to the realm of the mental.
A teacher needs to do much to prepare and use methods by which sensation can be stimulated and direction to the student's mind. He has to make the information meaningful and has the power to take sensations and make them into mental products themselves called percepts. A percept is a sensation which, through the self-activity of a conscious being, has taken on meaning in his consciousness. The cultivation of interpretation is almost unlimited as the learner is led to see the meaning of sensations impinging upon his brain.
The teacher selects stimuli and directs and guides the learner. Teaching involves changing the person who is learning from what he is to what he should become.