In this discussion, induction and deduction have been treated, for the sake of clearness, as if they acted independently of each other, as if a thinker might at one time use deduction and at another time induction.  They have been outlined in such a way that one might think that the movement of the mind in one process was such that it precluded the possibility of the other process.  This is not so—­the two are inextricably mingled in the actual process of reasoning, and further, induction as used in practical life always involves deduction at two points, as an initial starting point and as an end point.  The knowledge that a certain principle is inadequate comes to consciousness through the attempt to classify some particular experience under it.  Failure results and the inductive process may then be initiated, but this initial attempt is deductive and if it had been successful there would have been no need of induction.  After the inductive process is complete and the general principle has been classified or perfected, the final step is testing it to see if it is adequate, first by applying it to the particular problem which caused the whole process, and then to new situations.  If it tests, it is accepted,—­if not, further induction is necessary.  This again is deduction.  Not only is induction not complete without deduction, but each deduction influences the principle which is applied, making it more sure and more flexible.  Even in the process of induction, there are attempts to classify these facts which are being gathered under suggested old principles, or half-formed new ones, before the process is completed.  This is a deductive movement, even though it prove unsatisfactory or impossible.  Dewey describes this interaction by saying, “There is thus a double movement in all reflection:  a movement from the given partial and confused data to a suggested comprehension (or inclusive) entire situation; and back from this suggested whole—­which as suggested is a meaning, an idea—­to the particular facts, so as to connect these with one another and with additional facts to which the suggestion has directed attention."[10] However true this intermingling of induction and deduction may be, the fact still remains true that in any given case the major movement is in one direction or the other, and that therefore in order to insure effective thinking measures must be taken accordingly.  As a child formulates his conception of a verb, or words the characteristic essentials of the lily-family, or frames the rule for addition of fractions or the action of a base on a metal, he is concerned primarily with the form of the reasoning process known as induction.  When he classes a certain word as a conjunction, a certain city as a trade center, a certain problem as one in percentage, he is using deduction.  Complexes and gradual shadings of one state into another, not clearly defined and sharply differentiated processes and states, are characteristic of all mental life.