1887] Scientific Fact and Scientific Inference. 797 
tion occupies almost their sole attention. Many, indeed, get no 
_ farther than this, and are little more than observing machines. 
_ When they do go outside this line it is always with more or less ` 
= caution, because they well know that if their inferences be not — 
_ truths they will soon be disproved. Trained to deal with facts, 
they are constantly using observation as checks and guides to 
their speculation, and after any conclusion is reached or any 
theory made it must meet thousands of unthought-of observa- 
tions from nature, and be found to fall in with them all in perfect 
rmony before it can stand as an accepted scientific conclusion. 
In this they differ from metaphysical or philosophical inferences. 
If one theologian differs from another, each can think the other 
mistaken without the possibility of proof, for the necessary facts 
are beyond their reach, and the different stand-points of the two 
give, each, a different view. But if one scientist differs from an- 
other, it is frequently only a matter of a few years when further 
collections from nature’s store of facts will refute the position of 
one, or perhaps both. Here, then, there is a possibility of veri- 
fying the realm of thought by the realm of fact. Observations 
_ re made, and the mind works them over and draws conclusions 
_ ftom them, creating usually a thought to explain them. Then 
_ nce more it turns to observations to see if the thought created 
for a few facts will explain all, and thus have the force of a 
Seneral truth. When Darwin first conceived the theory which 
afterwards made his name famous, it was from a few observations 
i TROR the geographical distribution of animals; but, having con- 
 æived a thought which explained these facts, he spent twenty , 
years in patient application of this thought to all other classes 
of observation, and it was not till he had satisfied himself that 
_ the conclusion did harmonize with all the facts which he could 
a Collect that he was ready to let it be known. When the theory 
Was finally given to the world its great force was in this very 
fact, that it was shown to be in such accord with numerous facts 
4 s e; and what prevents it from being universally accepted 
: Duy 1s that there are still some facts which do not seem in 
Senordnice with the theory. : 
ne us it is with all scientific theories which have any authority. 
_ —'Sté is always a world of observation to be considered, which 
Pips = found in harmony with the conclusions. So cogent do 
5 ; conclusions sometimes become that they not only enable 
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