242 WORLD BUILDING 



selective tendency at work in a comparatively simple 

 problem, viz. the hydrodynamical theory of the ocean. 

 At first sight the problem of what happens when the 

 water is given some initial disturbance depends solely on 

 inorganic laws; nothing could be more remote from the 

 intervention of conscious mind. In a sense this is true; 

 the laws of matter enable us to work out the motion 

 and progress of the different portions of the water; and 

 there, so far as the inorganic world is concerned, the 

 problem might be deemed to end. But actually in 

 hydrodynamical textbooks the investigation is diverted 

 in a different direction, viz. to the study of the motions 

 of waves and wave-groups. The progress of a wave is 

 not progress of any material mass of water, but of a 

 form which travels over the surface as the water heaves 

 up and down; again the progress of a wave-group is not 

 the progress of a wave. These forms have a certain 

 degree of permanence amid the shifting particles of 

 water. Anything permanent tends to become dignified 

 with an attribute of substantiality. An ocean traveller 

 has even more vividly the impression that the ocean is 

 made of waves than that it is made of water.* Ulti- 

 mately it is this innate hunger for permanence in our 

 minds which directs the course of development of 

 hydrodynamics, and likewise directs the world-building 

 out of the sixteen measures of structure. 



Perhaps it will be objected that other things besides 

 mind can appreciate a permanent entity such as mass; 

 a weighing machine can appreciate it and move a 

 pointer to indicate how much mass there is. I do not 

 think that is a valid objection. In building the physical 

 world we must of course build the measuring appliances 



* This was not intended to allude to certain consequential effects of 

 the waves; it is true, I think, of the happier impressions of the voyage. 



