204 COSMIC PHILOSOPHY. |pt. I 



laws of aggregation of heterogeneous molecules. And we 

 see, moreover, that astronomy is merely the application of 

 the principles of molar physics (and, in its latest researches, 

 of molecular physics and chemistry also) to the study of a 

 special class of concrete phenomena. Such is the logical 

 arrangement ; and the only historical parallelism to be found 

 is the fact that theorems relating to masses were readied 

 sooner than theorems relating to molecules. 



It would not be difficult to cite other instances in which 

 the Comtean classification is at variance not only with the 

 order of the phenomena classified but also with the order of 

 historic progression. But I prefer to quote from Mr. Spencer 

 a remarkable passage which strikes immediately at the vital 

 point of the theory. Comte's fundamental error was in not 

 recognizing " the constant effect of progress in each class 

 upon all other classes ; but only on the class succeeding it 

 in his hierarchical scale. He leaves the impression that, with 

 trifling exceptions, the sciences aid each other only in the 

 order of their alleged succession. But in fact there has been 

 a continuous helping of each division by all the others, and 

 of all by each. Every particular class of inquirers has, as it 

 were, secreted its own particular order of truths from the 

 general mass of material which observation accumulates; 

 and all other classes of inquirers have made use of these 

 truths as fast as they were elaborated, with the effect of 

 enabling them the better to elaborate each its own order of 

 truths. It was thus with the application of Huyghens's 

 optical discovery to astronomical observation by Galileo. It 

 was thus with the application of the isochronism of the 

 pendulum to the making of instruments for the measuring of 

 intervals, astronomical and other. It was thus when the 

 discovery that the refraction and dispersion of light did not 

 follow the same law of variation, affected both astronomy and 

 physiology by giving us achromatic telescopes and micro* 

 scopes. It was thus when Bradley's discovery of the aberra- 



