been noted, some psychologists have used the terms thinking and reasoning as synonyms, but such usage has resulted in confusion and has not been of practical value.  It is only as the mental process desired becomes clearly conceived of, its connotations and denotation clearly defined, that it becomes a real goal towards Which a teacher or learner may strive.  This, then, is the primary criterion of reasoning—­that the thinker be dealing consciously with laws and principles.  An acceptance of this first essential makes clear that the particular process of reasoning cannot be carried on in subjects which lack laws and principles.  Spelling, elementary reading, vocabulary study, most of the early work in music and art, the acquisition of facts wherever found—­these situations may offer opportunity for thinking, but little if any for reasoning.  Because a teacher is using the development method does not mean necessarily that her students are reasoning.  The two terms are not in any way synonymous.

The second essential in reasoning is the presence of a definite technique.  This technique consists of two factors:  first, certain definite mental states, and second, the use of the process of thinking by either the inductive or the deductive method.

First as to the mental states involved.  The fact that the thinking deals with laws and principles necessitates the presence, in the thinking process, of constructive verbal or symbolic imagery, logical relationships, logical concepts, and explicit judgments.  This does not at all exclude other types of these mental states and entirely different mental states.  The kind of analysis involved simply necessitates the presence of these types, whatever others may be present.  Constructive symbolic imagery has already been discussed.  Logical relationships are those that are independent of accidental conditions, are not dependent on mere contiguity in time and space, but are inherent in the association involved.  Such relationships are those of likeness and difference, cause and effect, subject and object, equality, concession, and the like.  Logical concepts are those which are the result of thinking, whose definite meaning has been brought clearly into consciousness so that a definition could be framed.  A child has some notion of the meaning of tree, or man, or chemist, and therefore possesses a concept of some kind, but the exact meaning, the particular qualities necessary, are usually lacking, and so it could not be called a logical concept.  Explicit judgments are those which contain within themselves the reasons for the inference.  They, too, are the result of thinking.  One may say that “cheating is wrong,” or that “water will not rise above its source level,” or that “cleanliness is necessary to health,” or that “this is a Rembrandt”—­as a matter of experience, habit, but without any reflection and with no reasons for such judgment.  If, on the other hand, the problems to which these judgments are answers had been a matter of thinking, the reasons or the ground for such judgment would have become conscious and the judgment then become explicit.  It must be evident that in any problems dealing with laws and principles the mental states involved must be definite, clear cut, logically sound, and their implications thoroughly appreciated and understood.