&2 HABIT AND INTELLIGENCE. [chap. 



of sun's exhausted like that of a fire that dies out for want of fuel ; 

 subversion ^^^ ^^^^^' ^^'^^^ what evidence we have, appears the most 

 of equili- probable alternative. Or if the supply of meteors is in- 

 the solar definitely great, the increase of the sun's mass by their 

 system. falling in will subvert the equilibrium of the solar system. 

 And in neither case will the future be like the past and 

 the present. 



We have seen that the law of the conservation of energy 

 proves that the sun is radiating away his stock of heat, 

 and cannot possibly receive any considerable fresh supply 

 except from without. And we have seen that the law of 

 the dissipation of energy proves that the heat thus radiated 

 away tends to equilibrium — to equality of temperature 

 among all the bodies in the universe; and this involves 

 destruction of motive power. ^ 

 Is tlie Are we then to infer that all things are tending to 



^^"^ rt'^i^^ equilibrium, repose, and death ? 



Uncertain. ^^ ^^^^ Subject we Can only make conditional assertions, 

 as we do not and cannot know all the data. 

 Three cases are possible. 

 First case. The universe may be finite in the midst of infinite space. 



In this case all the heat will be radiated away. 

 Second The Universe may be finite in finite space. Space is no 



case. doubt geometrically infinite ; but the space in which our 



universe exists may, for anything we know to the contrary, 

 be boimded by space which is not pervious to radiance. 

 In this case the heat will ultimately attain to equilibrium, 

 and cease to be motive power. 



In either of these two cases all things are tending to 



equilibrium of temperature, destruction of motive power, 



Thii-d case, repose, and death. But a third case is possible, and has 



been hinted at in speaking of the possibility of an infinite 



supply of meteors being brought in from infinite space. 



The universe may be infinite, and in infinite space ; the 



supply of motive power may be infinite, and may last 



Each through endless time. In that case, however, though the 



separate whole universe is immortal, every separate system of which 



mortal it is composed must perish, as already explained, through 



1 See p. 56. 



