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the part of man ; that several of the natural crystallised 
minerals have now been formed artificially ; and that there is 
good reason for thinking that the earth was, in former ages, 
in a very different condition, — a condition in which the 
presence of water combined with a high temperature was 
eminently favourable to crystallisations which can hardly now 
take place. A person such as I have now supposed would 
naturally attribute the presence of the crystals in the cavities 
of the . mine to the ordinary processes of crystallisation ; he 
would look on the present state of things as something evolved, 
under the operation of the ordinary physical laws, out of a 
prior state that was different. 
Let us turn now to another example, in part imaginary. 
Suppose that we knew nothing of the earth and planets, except 
their motions in accordance with the law of gravitation, and 
nothing of the nebulas, and did not know that the solar radia- 
tion involves an expenditure of energy which has in some way 
to be accounted for. The motions of the bodies of the solar 
system can be calculated years beforehand, as is done in the 
Nautical Almanac Office, and in the same way their places 
years ago can be inferred from their present known orbits. 
In the supposed state of our knowledge, there would be 
nothing to indicate that they might not continue their motions 
for ever in the same way, or that the present state grew out of 
a previous state which was different. If the question were 
asked, How came they to be as they are ? one man might 
answer, They were always so ; another, They were created as 
they stand. Of course it would remain possible that the 
present state might have grown out of a previous different 
state merely in accordance with existing physical laws, but 
there would be nothing (under the supposed limitation of our 
knowledge) to justify us in assuming that it did. And if a 
further accession to our knowledge precluded, as it does pre- 
clude, the supposition that the planets have been always just 
as they are, the other two alternatives remain, that they were 
created as they stand, or that they grew into their present 
condition by the operation of physical laws out of a previous 
different state. If there were no indications of growth out 
of a different state we should not be justified in assuming 
that it was thus that they came into their present condition, 
though of course neither could we assume the contrary. On 
the supposition that they grew, the question, What was that 
previous state ? and. How grew they out of it ? is one belong- 
ing to the province of science, whether science can or cannot 
find a satisfactory answer; on the other supposition, the 
question is one with which science has nothing to do, as it 
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