138 THE GRAMMAR OF SCIENCE 



proven hypothesis. It is one, however, as we have seen, 

 suggested by the contemporaneous growth of perception 

 and reason, and strengthened by the impossibihty of any 

 form of perceptive faculty, such as we find in the insane, 

 surviving in the struggle for existence (p. 104). 



While invariable order in the sequence of sense-im- 

 pressions is thus seen to be an essential characteristic of 

 the perceptive faculty of a rational being, the power to 

 understand the why and wherefore of any sequence is 

 not so. It would undoubtedly be of great intellectual 

 interest to know why bodies fall to the earth, but Jiozv 

 they invariably fall is the practical knowledge, which now 

 enables us to build machines and which enabled our fore- 

 fathers to throw stones, and thus helped them as it helps 

 us in the struggle for existence. Broadly speaking, here 

 as elsewhere, the perceptive faculty has developed along 

 lines which strengthen man's powers of self-preservation 

 and not along those which would merely minister to his 

 intellectual curiosity. 



Anything, be it noted, that tends to weaken our con- 

 fidence in the uniform order of phenomena, in what we 

 have termed the routine of perceptions, tends also to 

 stultify our reasoning faculty by destroying the sole basis 

 of knowledge. It decreases our power of foresight and 

 lessens our strength for the battle of life. For this reason 

 theosophists and spiritualists with their modern miracles 

 contradicting the long-experienced routine of perceptions 

 are very unlikely to form a society sufficiently stable to 

 survive in the struggle for existence. Every ecstatic and 

 mystical state weakens the whole intellectual character of 

 those who experience it, for it impairs their belief in the 

 normal routine of perceptions. The abnormal perceptive 

 faculty, whether that of the madman or that of the mystic, 

 must ever be a danger to human society, for it under- 

 mines the efficiency of the reason as a guide to conduct. 

 Conviction, therefore, of the uniform order of phenomena 

 is essential to social welfare. 



But the reader may object that although this con- 

 viction be essential to social welfare, it does not follow 



