358 LAPLACE. 



analysis. No philosopher, no mathematician, could have 

 maintained himself more cautiously on his guard against 

 a propensity to hasty speculation. No person dreaded 

 more the scientific errors which the imagination gives 

 birth to, when it ceases to remain within the limits of 

 facts, of calculation, and of analogy. Once, and once 

 only, did Laplace launch forward, like Kepler, like 

 Descartes, like Leibnitz, like BufFon, into the region of 

 conjectures. His conception was not then less than a 

 cosmogony. 



All the planets revolve around the sun, from west to 

 east, and in planes which include angles of inconsiderable 

 magnitude. 



The satellites revolve around their respective prima- 

 ries in the same direction as that in which the planets 

 revolve around the sun, that is to say, from west to east. 



The planets and satellites which have been found to 

 have a rotatory motion, turn also upon their axes from 

 west to east. Finally, the rotation of the sun is directed 

 from west to east. We have here then an assemblage 

 of forty-three movements, all operating in the same di- 

 rection. By the calculus of probabilities, the odds are 

 four thousand millions to one, that this coincidence in the 

 direction of so many movements is not the effect of acci- 

 dent. 



It was Buffon, I think, who first attempted to explain 

 this singular feature of our solar system. Having wished, 

 in the explanation of phenomena, to avoid all recourse 

 to causes which were not warranted by nature, the cele- 

 brated academician investigated a physical origin of the 

 system in what was common to the movements of so 

 many bodies differing in magnitude, in form, and in dis- 

 tance from the principal centre of attraction. He im- 



