Inter-Relations of Living Creatures 669 



Theoretical Aspects 



In connection with evolution it is often asked how Natural 

 Selection, i.e., Nature's sifting and singling, can be expected to act 

 on the little finicking details which are so characteristic of living 

 creatures. To this very reasonable question Darwin himself gave 

 the answer by the emphasis he laid on the web of life. For in the 

 gradually evolved and ever complexified system of inter-relations 

 there is a sieve of extraordinary delicacy, which will discriminate 

 between even minute fluctuations to the plus or the minus side. 

 An apparently trivial new departure is tested in reference to the 

 established system of inter-relations. A shibboleth may decide the 

 fate of a species. 



Another question often raised is as to the general progres- 

 siveness of evolution. There have been retrogressions, blind 

 alleys, lost races, but on the whole life has been slowly creeping 

 upwards through the ages. But why should it? This is a difficult 

 question. But may not part of the answer be found in the 

 gradual complexifying of the web of life? There is established 

 an external system of inter-relations which is always becoming 

 more intricate take the linkages between flowers and their insect 

 visitors in illustration and this forms the sieve by which varia- 

 tions are sifted. In the progress of mankind there is an external 

 registration of racial gains; there is throughout Nature just the 

 beginning of this an external systematisation of inter-relations 

 which we call the web of life. 



Finally, it is important to acquire as a habit of mind the 

 vision of the web of life. It is distinctively the scientific way of 

 looking at things, to appreciate their inter-relations, to see Nature 

 (and human life as well) as a vibrating system most surely and 

 subtly interconnected. But in addition to the influence on our 

 theoretical outlook, there is the practical importance of the idea 

 of inter-relations. If we are to persist and advance in civilisation, 

 we must pay more heed to the web of life, to all the strange junc- 

 tions in our lines of communications. We cannot play the game 



