I04 THE GRAMMAR OF SCIENCE 



brief formulae or laws. Within sufficiently wide limits the 

 intensity of the perceptive faculty appears in all forms of 

 life proportional to the reasoning faculty.^ A world of 

 sense-impressions in no way amenable to man's reason 

 would be very prejudicial to man's preservation. In this 

 plight a man, like an idiot or insane person, would be 

 incapsible of analysis, or would analyse wrongly ; the 

 fitting exertion would not follow on the sense-impression, 

 and any such man would have small chance of surviving 

 among men whose perceptive and reasoning faculties were 

 attuned. Possibly some types of idiocy and madness are 

 the outcome of atavism, a return to variations of the 

 human mind in which perceptive and reflective faculties 

 are not co-ordinated — variations which on the whole have 

 been eliminated in the struggle for existence. If this 

 interpretation be at all a correct one — if, namely, the 

 perceptive faculty can be so moulded in the process of 

 evolution as to accept some and reject other sense- 

 impressions ; if, further, the perceptive and reflective 

 faculties have been developed in co-ordination, so that the 

 former accepts what, in wide limits, can be analysed by 

 the latter — then we have advanced some way towards 

 understanding why the routine of perceptions can be 

 expressed in brief formulae by the human reason. The 

 relation between natural law in the nomic (p. g'^, footnote) 

 and in the scientific sense becomes more intelligible when 

 we thus attribute the routine of the perceptions to the 

 machinery of the perceptive faculty. 



It will not, however, do to press this interpretation too 

 far ; or at least we must be careful to remember that, 

 while the perceptive faculty has developed the power of 

 solely perceiving sense-impressions capable of being dealt 

 with by the reflective faculty, it does not follow that they 

 have already been dealt with by the latter iaculty. Other- 



1 That woman has greater perceptive, man greater reflective power, is one 

 of those futilities which lias been used as an excuse for hindrances to woman's 

 development of both faculties. Exceptions of course there are, but the 

 general rule seems to be that the deeper the intellectual power in both sexes, 

 the wider is the range of perceptions and the more delicately sensitive is the 

 nervous system. 



