SENSATION AND PERCEPTION 121 



to events that occur in the external world that is (more or less) 

 '' made." The intervals of duration called days in the life of a 

 man are not, in general, the same to him since '' time passes " 

 more or less quickly, and the part of the passage of made inorganic 

 nature included between two successive transits of a fixed star 

 is taken as the standard interval of duration. Days, minutes, 

 seconds, years, centuries are points in the passage and duration 

 lies between these points. Much occurs in the life of a child 

 between two midsummer-night star transits and so " time is 

 long " ; less occurs, -in the same astronomical interval, in the 

 life of an old man and so " time flies." Astronomical time, then, 

 is the framework in which the things that happen to the animal 

 are inserted. 



43^. The Intuition of Space. Space is the consciousness 

 of bodily mobility. All the movable things in the body of an 

 animal have receptor organs in them and so we have sensations 

 of the movements of these parts. Primitively, no doubt, the 

 sensations of the tensions of muscles that act against resistances 

 are parts of the mechanisms of behaviour. Thus when a man 

 uses a screwdriver he feels the resistance of the materials as he 

 forces the screw into its bed and he graduates the muscular tension 

 to avoid " stripping the thread." It is possible that in behaviour 

 on a low plane all this delicacy of action is automatic and does 

 not rise into consciousness. But in the higher levels of behaviour 

 the consciousness of the movements of the body becomes intuition 

 of space. 



The perception of space apparently comes from many species 

 of receptivity. There is spatial consciousness apart from vision 

 and had merely by walking, when the movements of the limbs 

 give us the intuition that the body which w^as formerly there is 

 now here, and the magnitude of the interval between " there " 

 and '' here " is felt from the amount of muscular force exerted, 

 while there is a parallel intuition of duration between the " then 

 — there," and the " now — here." Similarly the space-interval is 

 felt when the hand moves along, say, the paper on which one 

 writes, even when there may be no vision. Here again the 

 consciousness of muscular movement is had. There is intuition 

 of space had by hearing when one can make rough estimates of 

 the '* place " from which the sound comes by movements of the 



