THE SCIENTIFIC LAW 85 



savage differ widely from that of normal civilised man. 

 One half of the perceptions which the latter links together 

 in a law of nature may be wanting to the former. Our 

 law of the tides could have no meaning for a blind worm 

 on the shore, for whom the moon had no existence/ By 

 the contents and the manner of perception the law of 

 nature is essentially conditioned for each perceptive faculty. 

 To speak, therefore, of the universal validity of a law of 

 nature has only meaning in so far as we refer to a certain 

 type of perceptive faculty, namely, that of a normal human 

 being-. 



'to- 



§ 4. — Man as the Maker of Natural Law 



The other problem with which we are concerned is the 

 existence or non-existence of a scientific law before it has 

 been postulated. Here the reader will feel, perhaps, 

 inclined to remark : " Admitted that ' Nature ' is con- 

 ditioned by man's perceptive faculty, surely the sequences 

 of man's perceptions follow the same law whether man 

 has formulated that law in words or not ? The law of 

 gravitation ruled the motion of the planets ages before 

 Newton was born." Yes and no, reader ; the answer 

 must depend on how we define our terms. The sequences 

 involved in man's perception of the motion of the heavenly 

 bodies were doubtless much the same to Ptolemy and 

 Newton ; to primitive man and to ourselves the motion of 

 the sun is a common perception, but a sequence of sense- 

 impressions is not in itself a law. That planets move, 

 that a chick takes its origin from the egg, may be 



1 This point is well brought out by Prof. Lloyd Morgan in his Animal 

 Life and Intelligence. After pointing out the widely different character of 

 the sense organs in man and insects he continues : — 



" Remember their compound eyes with mosaic vision, coarser by far than 

 our retinal vision, and their ocelli of problematical value, and the complete 

 absence of muscular adjustments in either one or the other. Can we conceive 

 that, with organs so different, anything like a similar perceptual world can be 

 elaborated in their insect mind ? I for one cannot. Admitting therefore 

 that their perceptions may be fairly surmised to be analogous, that their world 

 is the result of construction, I do not see how we can for one moment 

 suppose that the perceptual world they construct can in any accurate sense 

 be said to resemble ours" (pp. 298-9, 356-7, 361). 



