750 THE PRINCIPLES OF SCIENCE. [CHAP. 



Inconceivable ages might be required for the completion of 

 this process, but the dissipation of energy thus proceeding 

 could end only in the production of a cold and motionless 

 universe. The relation of cause and effect, as we see it 

 manifested in life and growth, would degenerate into the con- 

 stant existence of every particle in a fixed position relative 

 to every other particle. Logical and geometrical resem- 

 blances would still exist between atoms, and between 

 groups of atoms crystallised in their appropriate forms 

 for evermore. But time, the great variable, would bring 

 no variation, and as to human hopes and troubles, they 

 would have gone to eternal rest. 



Science is not really adequate to proving that such is 

 the inevitable fate of the universe, for we can seldom trust 

 our best-established theories far from their data. Never- 

 theless, the most probable speculations which we can 

 form as to the history, especially of our own planetary 

 system, is that it originated in a heated revolving nebulous 

 mass of gas, and is in a state of excessively slow progress 

 towards the cold and stony condition. Other speculative 

 hypotheses might doubtless be entertained. Every hypo- 

 thesis is pressed by difficulties. If the whole universe be 

 cooling, whither does the heat go ? If we are to get rid 

 of it entirely, outer space must be infinite in extent, so 

 that it shall never be stopped and reflected back. But not 

 to speak of metaphysical difficulties, if the medium of heat 

 undulations be infinite in extent, why should not the 

 material bodies placed in it be infinite also in number and 

 aggregate mass ? It is apparent that we are venturing into 

 speculations which surpass our powers of scientific inference. 

 But then I am arguing negatively ; I wish to show that 

 those who speak of the uniformity of nature, and the reign 

 of law, misinterpret the meaning involved in those expres- 

 sions. Law is not inconsistent with extreme diversity, 

 and, so far as we can read the history of this planetary 

 system, it did probably originate in heated nebulous matter, 

 and man's history forms but a brief span in its progress 

 towards the cold and stony condition. It is by doubtful 

 and speculative hypotheses alone that we can avoid 

 such a conclusion, and I depart least from undoubted 

 facts and well-established laws when I assert that, what- 

 ever uniformities may underlie the phenomena of nature, 



