THE WORLD OF LIVING ORGANISMS 129 



in principle is like the food-circle, only that what is set in 

 activity by the animal's " control " is not the feeding 

 apparatus, but the apparatus of sex. 



All the circles, however far they lie separated from one 

 another in the world-as-sensed, intersect in the steering- 

 apparatus of the inner world, and then separate from one 

 another again in the world of action. 



Biological treatment of the function-circles requires that 

 we also consider from the point of view of conformity with 

 plan that part of the circle which goes on outside the body 

 in the surrounding- world. We are accustomed to treat 

 things lying outside the subject according to the rules of 

 causality alone. But by so doing we are not taking account 

 of the biological framework, which is co-extensive with the 

 whole circle. 



Let us suppose that we wish to construct a complete 

 mechanical function-circle. Suppose, for instance, that we 

 furnish an automatic locomotive with an optical apparatus 

 capable of stimulation by the indications of red and green 

 railway signals, and thus affecting the steering of the engine ; 

 we should be obliged to construct the surrounding-world — 

 in this case the railway-track — in as exact conformity with 

 plan as the engine itself. 



Now animals are so much part and parcel of Nature that 

 even the surrounding-world works within the whole like a 

 part constructed in conformity with plan. 



We may assume that where there is a foot, there is also 

 a path ; where there is a mouth, there is also food ; where 

 there is a weapon, there is also an enemy. 



This last instance expresses a fact often misunderstood, 

 namely, that struggle belongs to the universal plan. In 

 opposition to what the Darwinian theory assumes, the 

 struggle for existence is not merely one cause in the causal 

 series, but an essential part of the general plan of life. 



I 



