10 THEORETICAL BIOLOGY 



in the muscles or joints. (Everyone knows that if you shut 

 your eyes and try to touch one forefinger with the other, you 

 often go wide of the mark.) As soon, however, as the first 

 local sign is aroused which is connected with the sensation of 

 touch, I become quite clear about the relations of this local 

 sign with the three planes of direction ; I am " orientated." 

 If now, at the moment when a series of local signs sounds, the 

 outer direction-signs belonging to them correspond, these 

 latter at once get their relation to the planes of direction, and 

 transform themselves into inner direction-signs ; but they do 

 this without assuming the character of our own movement- 

 sensations, because muscular sensations are lacking. 



The consequences of this identification of outer with inner 

 direction-signs are very important, for they enable us to bring 

 to a common measure our own movements and movements in 

 the outside world. If I run the ball of one finger along the 

 edge of the table, the inner and outer direction-signs begin to 

 sound together ; but they are opposite signs. If the outer 

 signs are " To the left . . . left . . . left," the inner signs 

 are " To the right . . . right . . . right." Then the effect 

 of the inner and outer signs, as an indication (index) of move- 

 ment, is nullified and I am aware only of my own movement. 

 The inner direction-signs unite with the outwardly transferred 

 touch-sensations, and I get the impression of my own move- 

 ment of touch along an unmoved object. 



(Whereas muscular feelings are referable to the condition 

 of one's own body, the sensations of touch with their very 

 precise local signs, serve as indications for properties of 

 the outside world.) 



Each local sign instructs us concerning one spot in our 

 own body, but it is the direction-signs which determine its 

 position in space. This fact is very obvious in the case of 

 our fingers while they touch things and are all the time chang- 

 ing their position. The tip of the forefinger has become extra- 



