The power to grow depends upon the need for others and plasticity. Both of these conditions are at their height in childhood and youth. Plasticity or the power to learn from experience means the formation of habits. Habits give control over the environment, and power to utilize it for human purposes. Habits take the form both of habituation, or a general and persistent balance of organic activities with the surroundings, and of active capacities to readjust activity to meet new conditions.

The former furnishes the background of growth; the latter constitutes growing. Active habits involve thought, invention, and initiative in applying capacities to new aims. They are opposed to a routine which marks an arrest of growth. Since growth is the characteristic of life, education is all one with growing; it has no end beyond itself. The criterion of the value of school education is the extent in which it creates a desire for continued growth and supplies means for making the desire effective in fact.

1 Intimation of its significance is found in a number of writers, but John Fiske, in his Excursions of an Evolutionist, is accredited with its first systematic exposition.

2 This conception is, of course, a logical correlate of the conceptions of the external relation of stimulus and response, considered in the last chapter, and of the negative conceptions of immaturity and plasticity noted in this chapter.