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was collected, may eventually prove most serviceable in the 
establishment of some other doctrine. This was the case with 
the false hypothesis of epicycles ; which, how r ever, proved of great 
service to a truer astronomy, by giving a mass of observations, 
which represented the velocities and places of the planets in a 
way not far from true, and also by giving knowledge sufficient 
to predict eclipses and construct astronomical tables. 
Such conjectures as those of the hypotheses of spontaneous 
generation, conservation of energy, or evolution, however they 
may by future observation be demonstrated as erroneous, will 
yet prove exceedingly useful by the most important facts they 
are accumulating in such large numbers ; they are, as it were, 
cutting from the quarry of nature a great quantity of building- 
material, which some future architect may erect into a noble 
and permanent building. But while fertile and intelligent 
conjecture is so advantageous to science, a bigoted adherence 
to these conjectures, when all evidence is against them, is just 
as pernicious to its interests, and arrestive of its progress. The 
character of the true naturalist is indicated by the words of 
Leslie, who said : “ In the course of investigation I have found 
myself compelled to relinquish some preconceived notions ; but 
I have not abandoned them hastily, nor till after a warm and 
obstinate defence, I was driven from every post.” He, of 
course, held on while he could ; but when he could no longer 
honestly hold his post, he abandoned it; an example much 
needed by some modern theorists. “ The candid and simple 
love of truth,” Whewell well remarks, “ which makes the dis- 
coverer willing to suppress the most favourite production of his 
own ingenuity as soon as it appears to be at variance with 
realities, constitutes the first characteristic of this temper. He 
must neither have the blindness which cannot, nor the obstinacy 
which will not, perceive the discrepancy of his fancies and his 
facts. He must allow no indolence, or partial views, or self- 
complacency, or delight in seeming demonstration, to make him 
tenacious of the schemes which he devises, any further than 
they are confirmed by their accordance with nature. The 
framing of hypotheses is, for the inquirer after truth, not the 
end, but the beginning of his work.” Having then framed an 
hypothesis, the next step is to test it by contact with fact, to 
verify the correctness of our inferences by further observation 
or experiment; to examine by an appeal to nature whether the 
conclusion at which we have arrived is in harmony with the 
evidence at our disposal. In other words, we must now proceed 
deductively from the intellect to the senses, from an imagined 
law to its consequences. By induction we have bounded to the 
