564 Scientific Proceedings^ Royal Dublin Society. 



The hypothesis points to a time when there will be no more 

 progressive change but a mere sequence of unfruitful events, 

 such as the eternal uniform motion in reference to the ether 

 around it of a mass of matter no longer gaining or losing heat : 

 to an ether possessed of a uniform distribution of energy in 

 all its parts ; a uniform distribution, of unceasing but unfruitful 

 interactions, wherein the material aggregations, if not all one, yet 

 in perfect equilibrium or sundered by iufinitj^, move as unceas- 

 ing and unchanging waves of unfruitful energy. Or, again, if 

 the ether absorb the energy of material" motion, these vast and 

 dark aggregations eternally poised and at rest within it. This is, 

 physically, a thinkable future. Our minds suggest no change, 

 and demand none. More than this, change is unthinkable accord- 

 ing to our present ideas of energy. 



This finality a parte pod is instructive. Abstract considera- 

 tions, based on geometrical or analytical illustrations, question 

 the finiteness of some physical developments. Thus our sun may 

 require eternal time to attain the temperature of the ether around 

 it, the approach to this condition being assumed to be asymptotic 

 in character. But consider the legitimate reductio ad absurdnm of 

 an ember raked from a fire 1000 years ago. Is it not yet cooled 

 down to the constant temperature of its surroundings ? But we 

 may evidently increase the time a million-fold if we please. It 

 appears to me that we must regard eternity as outliving every 

 progressive change. For there is no convergence or enfeeblement 

 of time. The ever-flowing present moves no differently for the 

 occurrence of the mightiest or the most insignificant events. And 

 even if we say that time is only the attendant upon events, yet 

 this attendant waits patiently for the end, however long deferred. 



Does the essentially material hypothesis of Kant and Laplace 

 account for an infinite past as thinkably as it accounts for the 

 infinite future ? As this hypothesis is based upon material 

 instability the question resolves itself into this : — Is the assump- 

 tion of an infinitely prolonged past instability a probable or 

 possible account of the past? There are, it appears to me, great 

 difficulties involved in accepting the hypothesis of infinitely pro- 

 longed material instability. I will refer here to three principal 

 objections. The first may be called a metaphysical objection; 

 the second is partly metaphysical and partly physical, the third 



