626 ADDRESS OF PROFESSOR LOVERING. 
lution as a mechanical doctrine, capable of explaining certain 
characteristics of the solar system, about which the law of gravi- 
tation is silent. Whoever reads the stately chapters of Laplace, 
on the stability of the planets and the safeguards of the comets, 
will easily recognize expressions which are the mechanical equiv- 
alents of the principles of natural selection and the survival of 
the fittest. The elder Herschel hazarded the speculation, that the 
clusters of stars and the nebule which his devouring telescope 
had picked .up, by hundreds, on the verge of the visible heavens, 
“were genuine suns assembled under the organizing power of 
gravitation; and that the varieties in size, shape, and texture, 
were produced by differences of age and distance. The imagi- 
nation of Herschel and other astronomers has taken a loftier 
flight. To them many of the nebule are not clusters of stars, but 
unborn solar systems, waiting for that consolidation by which 
planets are ‘evolved and a central sun is formed, and destined thus 
to repeat the cosmogony of the home system. Comte claims that 
he has raised the nebular hypothesis to the rank of positive sci- 
ence. He supposes the stupendous enginery of evolution to be 
reversed. He follows, with his mathematics, the expanding sun 
backwards into chaos, until it has absorbed into its bosom even 
the first born among the planets, and finds, at every stage, numer- 
ical confirmation of what Laplace threw out as a plausible cone 
jecture. As Mr. Mill and other writers of note have accepted this 
authority, it should be understood that Comte has never published 
the data or the process of his computations, By whatever other 
inspiration he arrived at his conclusion, he was not brought to it 
by his mathematics. He has said all that is necessary to show 
that he ignored all the difficulties of the problem, and dodged the 
only solution that could give satisfaction. The cosmogony of 
Laplace, with all its fascination, must be excluded from exact 
mechanics and remanded back to its original place in mone 
history, by the side of the more general nebular hypothesis ai 
Herschel. All other cosmogonies which poetry or science a 
invented are childish in comparison with this: and no one woul 
desire to banish it from science altogether, until it is disproved ° 
displaced by something better. Instead of deciding, it must share 
the fate of the all-embracing cosmical speculation of Halley. 
How uncertain that fate is we may be taught by the frequency 
with which the preponderance of evidence has shifted from 
