Though questioning is the most valuable of teaching devices, it is quite susceptible of being overworked. There is quite as much danger of using it too extensively as there is of using it too little. Frequently, teachers try to question from pupils what they could not be expected to know. Further, it is possible by too much questioning to cover up the point of the lesson rather than reveal it, and to mystify the pupils rather than clarify their ideas. These are the two main abuses of the device. After all, it should be remembered that, important as good questioning undoubtedly is, it is not the only thing in lesson technique. In teaching, as elsewhere, variety is the spice of life. Sympathy, sincerity, enthusiasm in the teacher will do more to secure mental activity in the pupils than mere excellence in questioning. The energetic, enthusiastic, sympathetic teacher may secure better results than the teacher whose ability in questioning is well-nigh perfect, but who lacks these other qualities. If, however, to these qualities he adds a high degree of efficiency in questioning, his success in teaching is so much the more assured. PART III. EDUCATIONAL PSYCHOLOGY CHAPTER XIX CONSCIOUSNESS =Data of Psychology.=--Throughout the earlier parts of the text, occasional reference has been made to various classes of mental states, and to psychology, as the science which treats of these mental states, under the assumption that such references would be understood in a general way by the student-teacher. At the outset of a study of psychology as the science of mind, however, it becomes necessary to inquire somewhat more fully into the nature of the data with which the science is to deal. Mind is usually defined either by contrasting it with the concrete world of matter, or by describing its activities. It is said, for instance, that mind is that which feels and knows, which hopes, fears, determines, etc. By some, indeed, mind is described as merely the sum of these states of knowing and feeling and willing. The practical man says, however, _I_ know and feel so-and-so, and _my_ wish is so-and-so. Here an evident distinction is drawn between the knower, or conscious self, and his conscious activities. While, however, we may agree with the practical man that there is a mind, or self, that knows and wills and feels; yet it is evident that the self, or knower, can know himself only through his conscious states. It must be understood, therefore, that mind in its ultimate sense cannot be studied directly, but only the conscious states, or conditions of mind. Thus psychology becomes a study of mental states, or states of consciousness; and it is, in fact, frequently described as the science of consciousness.