OCTOBKE 3, 1902.] 



SCIENCE. 



539 



may iu future be superseded or absorbed 

 by a wider generalization. It is only the 

 poverty of language and the necessity for 

 compendious expression that oblige the 

 man of science to resort to metaphor and to 

 speak of the LaAvs of Nature. In reality, 

 he does not pretend to formulate any laws 

 for Nature, since to do so would be to as- 

 sume a knowledge of the inscrutable cause 

 from which alone such laws could emanate. 

 When he speaks of a 'law of Nature' he 

 simply indicates a sequence of events which, 

 so far as his experience goes, is invariable, 

 and which therefore enables him to pre- 

 dict, to a certain extent, what will happen 

 in given circumstances. But, however 

 seemingly bold may be the speculation in 

 which he permits himself to indulge, he 

 does not claim for his best hypothesis more 

 than provisional validity. He does not 

 forget that to-morrow may bring a new 

 experience compelling him to recast the 

 hypothesis of to-day. This plasticity of 

 scientific thought, depending upon reverent 

 recognition of the vastness of the unknown, 

 is oddly made a matter of reproach by the 

 very people who harp upon the limitations 

 of human knowledge. Yet the essential 

 condition of progress is that we should 

 generalize to the best of our ability from 

 the experience at command, treat our 

 theory as provisionally true, endeavor to 

 the best of our power to reconcile with it 

 all the new facts we discover, and abandon 

 or modify it when it ceases to afford a co- 

 herent explanation of new experience. 

 That procedure is far as are the poles 

 asunder from the presumptuous attempt to 

 travel beyond the study of secondary 

 causes. Any discussion as to whether mat- 

 ter or energy was the true reality would 

 have appeax-ed to Tyndall as a futile meta- 

 physical disputation, which, being com- 

 pletely dissociated from verified experi- 

 ence, would lead to nothing. No explana- 

 tion was attempted by him of the origin 



of the bodies we call elements, nor how 

 some of such bodies came to be compounded 

 into complex groupings and built up 

 into special structures with which, so far 

 as we know, the phenomena characteristic 

 of life are invariably associated. The evo- 

 lutionary doctrine leads us to the conclu- 

 sion that life, such as we know it, has only 

 been possible during a short period of the 

 world 's history, and seems equally destined 

 to disappear in the remote future; but it 

 postulates the existence of a material uni- 

 verse endowed with an infinity of powers 

 and properties, the origin of which it does 

 not pretend to account for. The enigma 

 at both ends of the scale Tyndall admitted, 

 and the futility of attempting to answer 

 such questions he fully recognized. Never- 

 theless, Tyndall did not mean that the man 

 of science should be debarred from specu- 

 lating as to the possible nature of the sim- 

 plest forms of matter or the mode in which 

 life may have originated on this planet. 

 Lord Kelvin, in his presidential address, 

 put the position admirably when he said 

 'Science is bound by the everlasting law 

 of honor to face fearlessly every problem 

 that can fairly be presented to it. If a 

 probable solution consistent with the ordi- 

 nary course of Nature can be found, we 

 must not invoke an abnormal act of Crea- 

 tive Power'; and in illustration he forth- 

 with proceeded to express his conviction 

 that from time immemorial many worlds 

 of life besides our own have existed, and 

 that 'it is not an unscientific hypothesis 

 that life originated on this earth through 

 the moss-grown fragments from the ruins 

 of another world.' In spite of the great 

 progress made in science, it is curious to 

 notice the occasional recrudescence of meta- 

 physical dogma. For instance, there is a 

 school which does not hesitate to revive 

 ancient mystifications in order to show that 

 matter and energy can be shattered by 

 philosophical arguments, and have no ob- 



