MENTAL SYSTEMS 37
likely to become more and more critical and extensive as his experience broadens and his activities become more varied in the more complex relations of life. The boy that grows up on a farm soon comes to have vague notions of the several kinds of animals and tools used and of the several kinds of crops raised on the farm. He comes to know about horses, cows, pigs, fowls ; plows, wagons, reapers, buggies; wheat, corn, oats, potatoes, etc. And he acquires crude notions of their relations to one another, and of the relations and functions of the farm as a whole. With the passing of the months his concepts of these various objects and of their relations to one another become more adequate, more definite, more distinct, through actual dealing with them. By visits to the neighbouring town he becomes vaguely acquainted with other modes of life; and as he takes an increasing share both in raising the products of the farm and in marketing them in the town his concept of the farm and its relation to the rest of the world is enriched. His childish notions are undergoing continuous revision, and becoming larger and more complex. His mental system is passing through the double process of, first, unreflective organization and, second, reflective reorganization as the exigencies of his broadening experience require; but it remains as yet mainly unreflective in character. By and by he is sent for education to the agricultural college; and there he studies the principles of farming as they have been sifted and formulated by experts from the general experience of men. He learns the chemical composition of various soils and the adaptation of the several kinds of seeds to the several kinds of soil, and the most approved methods of cultivation and the chemical and biological laws underlying these methods. He sees farming conducted according to these principles and critically observes the processes. He is instructed as to the relation of agriculture to the general economic and cultural order of society. His system of ideas relating to that general field of experience has now been reflectively reorganized with approximate thoroughness. He
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