42 THEORETICAL BIOLOGY 



number of direction-steps for the human eye when it is 

 moving. 



This is how space appears as we make use of it in vision. 

 But since we are able to transfer ourselves in thought with 

 this intuited space to every place we look at, we transform 

 space into a continuous series of places. Space as we think 

 of it is the space with which the physicist deals, while intuited 

 space as we look at it is the space of the biologist. The two 

 are fundamentally different from one another. 



It is only intuited space that comes into consideration 

 in investigating animals. We shall try to decide whether 

 animals have three, two or one plane of direction, or whether 

 they have none at all and perhaps substitute for them the 

 line of the horizon. Further, we shall investigate the means 

 which animals have at their disposal for making steps-into- 

 distance. Lastly, we must discover the number and the 

 distribution of the places in animal space. Only when all 

 these factors are known, can we affirm that we have gained 

 an insight into the spatial world of animals. 



Every spatial animal world, however limited as regards 

 places and steps-into-distance, and even though it be without 

 planes of direction, is nevertheless surrounded by the pure 

 extended, which, as necessary form, precedes all space- 

 creating. The extended lies immediately behind the last 

 step-into-distance. So the space peculiar to each animal, 

 wherever that animal may be, can be compared to a soap- 

 bubble which completely surrounds the creature at a greater 

 or less distance. The soap-bubble of the extended constitutes 

 for the animal the limit of what for it is finite, and therewith 

 the limit of its world ; what lies behind that is hidden in 

 infinity. 



In entering on the attempt to establish these matters 

 concerning the space of animals, we make no declaration as 

 to the manner in which the animal consciously intuits space 



