Page:Mind (New Series) Volume 15.djvu/75

PRESENTATION AND REPRESENTATION. 61 I system of minor systems ; the small circles representing the elementary nervous parts, and the groups of small circles the minor systems within the great system. As we know, these minor systems are more or less intimately correlated. A certain group of minor systems (indicated by A in the dia- gram) has special relation to the stimulation of the whole system from its environment ; another group of minor sys- tems (indicated by P in the diagram) has special relation to the reaction of the whole system upon its environment ; while another and vastly more complex group of minor systems (indicated by B in the diagram) functions in the co-ordina- tion of the activities of the minor systems of group A, with the activities of the minor systems of group F. If we assume a thorough-going correspondence between the activities within the man's nervous system and his con- sciousness, then this diagram may also be used, as I shall use it below, to refer to our psychic states. -B- oo oooooo oo o ooooooo ooo oooo oo o oo oo oo oo ) O O OOO OOO OOO OOO I oo oo oo oo oo I OOOOOO 00 o o oooooooooooo ooo oo oooo oooo oo PIG. 1. When our nervous system receives a stimulus from the environment through one of the sensory organs, we may sup- pose the emphatic activities, resulting from the stimulation to be symbolised by the darkened portions of the above dia- gram (fig. 1). These activities as a whole we may well call primary reactions. The main emphasis of activities (indicated by the large O in fig. 1) is seen in the parts directly acted upon by the environmental stimuli ; but the main system is also involved to some extent in the total primary reaction. Now it is quite conceivable that the parts of the main system thus emphatically active in connexion with the primary reaction may, under other conditions, become em-