76 THE LIMITATIONS OF SCIENCE 



magnitude of its units, which permits such an abstract 

 simplification of matter as to consider it merely in the 

 form of masses concentrated at mathematical points. 

 Where we deal with bodies measured in millions of 

 tons and with distances in millions of miles, such varia- 

 tions as are found in the laboratory sink into com- 

 parative insignificance and we can deal with averages 

 instead of particulars. On tEe whole their attempt was 

 a success since we can find few flaws in the general 

 conception of a nebular hypothesis, however we may 

 differ as to details. And just because the phenomena 

 discussed are so few in number and so general in char- 

 acter, there was not the need for supposititious causes 

 and fictitious attributes, provided we grant their initial 

 state of the universe and the first cause contributing to 

 irregularity and the beginning of motion. These pos- 

 tulates are of course entirely arbitrary and require 

 us to assume an existence previous to time, since time 

 has no meaning in a universe which is everywhere in a 

 state of perfect equilibrium and rest. Undoubtedly 

 the reason why this hypothesis persists in its principal 

 features to the present time, in spite of constant 

 attacks, is just because its authors exercised self- 

 restraint, holding to general laws and avoiding specific 

 details. Some form of cosmical evolution is now gen- 

 erally granted and the heavens are swept by gigantic 

 telescopes which linger on the nebulae, in the hope that 

 accurate measurement will show that these apparently 



