30 THE NEBULAE HYPOTHESIS. 



ably concurrent facts, pointing to the same conclusion as to 

 the origin of our planetary system, can not reasonably be set 

 down as so many mere fortuitous coincidences. 



Finally, the theory in question is the only one which does 

 not either involve inexplicable and inconceivable mysteries, or 

 suppositions totally unfounded in any of the known laws of 

 causation. This theory, on the other hand, commends itself 

 to human reason and intuition, without being encumbered with 

 any serious difficulties ; and, as it is confessedly unphilosophi- 

 cal to look for an explanation of a phenomenon without the 

 sphere of known natural laws, when a full explanation may 

 be found within the sphere of those laws, the nebular theory 

 may be considered as established, at least until it is invalidated 

 by further discoveries. 



