May 31, 1895.] 



SCIENCE. 



609 



kuow truth only through approximation, 

 the revision and extension of these sense 

 impressions. These impressions and the 

 inductions from them serve as guides to ac- 

 tion. In this relation these common im- 

 pressions must be true, because trust m 

 tliem has been safe. "Wrong action must 

 have led to the destruction of the actors. 

 One test of truth, perhaps the only one, is 

 the safety that comes from trusting it. The 

 power of choice implies that right choice 

 must be made. Only those who in the nar- 

 row range of choice choose safely can sur- 

 vive. To this end of safe choice, sensa- 

 tions, desires and reason must cooperate. 

 The adaptation to complex conditions rests 

 on the abilitj' of the individual to receive 

 the degree of truth he needs to make safe 

 choice possible, and no more. For truth- 

 fulness in sensation exists only in the range 

 within which action and choice are de- 

 pendent on it. Bej-ond this range truth 

 would have no value as an aid to adapta- 

 tion. Our senses tell us something of truth 

 as to bread and fi-uit and stones, which we 

 maj- use or touch or avoid. They do not 

 give us just impressions of the stare or sky. 

 which we cannot reach,nor of the molecule, 

 which we cannot grasp. Our sense powers, 

 as well as our powei-s of reasoning, are emi- 

 nently practical. They are bounded by the 

 needs of the lives of our ancestors, to whom 

 any form of hijperadhemi would have been 

 destructive and not helpful. 



The methods and the appliances of science 

 serve as an extension of the truthfulness of 

 the senses into regions in which truth was 

 not demanded for the life-purposes of our 

 ancestors. These methods yield truth of a 

 similar kind, which can be measured by 

 the same test. AVe maj' trust the informa- 

 tion given bj' the electrometer or the micro- 

 scope or the calculus just as implicitly as 

 we receive what our own eyes have seen or 

 our own hands have felt.- We may depend 

 on the truth given by these instruments of 



precision to a greater degree than on that 

 which the common senses furnish us, be- 

 cause the guards and checks on scientific ap- 

 pliances are more perfect. The information 

 gained bj' observation and sifted by reason 

 constitutes science. In the struggle for ex- 

 istence, knowledge is power. Our civiliza- 

 tion rests directly on the growth of scien- 

 tific knowledge and on the availability to 

 the individual of its accumulated power. 

 Its basis is the safetj- of trusting to human 

 experience. The ' Laws of Xature,' as we 

 know them, are generalizations of such ex- 

 perience. Their statement may form part 

 of a ' scientific creed ' to those who have 

 tested them, if such feel that ' I believe ' 

 adds force to ' I know.' 



The essence of the ' Monistic Creed ' as 

 set forth by Haeckel is not, as I understand 

 it, drawn from such sources. It is an out- 

 growth from Haeckel's pei-sonality, not from 

 his researches. So far as I know, no change 

 has taken place in it as a result of anj- dis- 

 cover}' its author has made. If its details 

 have been changed at any time since it was 

 first formulated, the reason for such change 

 must be sought for in Haeckel, not in Sci- 

 ence. 



Perhaps, indeed, there is " one spirit in 

 all things, and the whole cognizable world 

 is constituted and has been developed in ac- 

 cordance with one fundamental law." But 

 this is no conclusion of science. It rests on 

 no human experience. If it be the induc- 

 tion resulting from all human experience, 

 that fact has not been made plain to us. 

 The hj-perjesthesia of the microscope or the 

 Calculus brings one no nearer to it. Its 

 place is in the boundless realm of guess- 

 work. It value lies in tlie stimulus which 

 clever gtiesses give to the otherwise plod- 

 ding operations of scientific men. It seems 

 to me that ■ Monism ' belongs to the domain 

 of speculative philosophy, a branch of 

 thought which, according to Helmholtz, 

 deals witli such 'schlechtes stoft';' that its 



