CHAP, vii THE TWO ORDERS 109 



environment and changes in the organism resulting in 

 behaviour suited to the needs of the organism, yet nowhere 

 implying knowledge of what is going forward. So theo- 

 retically it is possible that there should be a point to point 

 correspondence between our thought, or any portion of our 

 thought, and the real order without a true apprehension 

 of that order. Indeed, if we take the scientific order as 

 real, we are directly forced to admit the existence of such 

 a correspondence at the lower stage of common sense, 

 wherever we arrive at sound practical conclusions by 

 methods or on grounds which are inadequate or false. The 

 familiar experience of day and night and the observed 

 position of the westering sun suffice to tell the savage that 

 the darkness is at hand, and he will take his measures 

 accordingly, and not a whit the worse because his mental 

 construction of the sun's movements is scientifically false. 

 The housewife can boil the kettle though she is innocent 

 as the babe of the thermal laws involved in the operation. 

 True, there are occasions on which the limitations of com- 

 mon sense will come into play. It is not prepared for all 

 the exceptions which science can understand and foresee, 

 and here the difference between a deeper and more super- 

 ficial knowledge will break out and have practical conse- 

 quences. Both in its successes and in its failures, the 

 structure of common-sense knowledge reveals itself as a 

 development adapted to the normal course of human 

 environment, and adapted primarily to action within that 

 environment and to understanding only as a means to 

 action. The circumstance, then, that common sense has its 

 validity as a practical guide is not to be taken, without 

 further parley, as evidence that it renders a true account 

 of our surroundings. It neither excludes this possibility 

 nor decides in favour of it. We may reach sound practical 

 conclusions from wrong theoretical premises. 



(b) There is a further point of great importance. Even 

 if our common-sense knowledge be sound as far as 

 it goes, it may also be very inadequate. It is, to begin 

 with, limited by perception. Now our perceptive faculties 

 grow up under the ordinary conditions of development 

 and they evolve apart from artificial selection and training 



