esistance, are all commoner facts than pumping; that light travels
faster than sound is a commoner fact than a thunderstorm or gun-firing.
Each of the laws--'Cats kill mice,' 'Mice destroy humble-bees' nests,'
'Humble-bees fructify red clover'--is wider and expresses the
resemblance of more numerous cases than the law that 'Clover depends on
cats'; because each of them is less subject to further conditions.
Similarly, every step in the communication of thought by language is
less conditional, and therefore more general, than the completion of the
process.

In all the above cases, again, each law into which the phenomenon
(whether pumping or conversation) is resolved, suggests a host of
parallel cases: as the modifying of air-waves by the larynx and lips
suggests the various devices by which the strings and orifices of
musical instruments modify the character of notes.

Subsumption consists entirely in proving the existence of an essential
similarity between things where it was formerly not observed: as that
the gyrations of the moon, the fall of apples, and the flotation of
bubbles are all examples of gravitation: or that the purifying of the
blood by breathing, the burning of a candle, and the rusting of iron are
all cases of oxidation: or that the colouring of the underside of a
red-admiral's wings, the spots of the giraffe, the shape and attitude of
a stick-caterpillar, the immobility of a bird on its nest, and countless
other cases, though superficially so different, agree in this, that they
conceal and thereby protect the organism.

Not any sort of likeness, however, suffices for scientific explanation:
the only satisfactory explanation of concrete things or events, is to
discover their likeness to others in respect of Causation. Hence
attempts to help the understanding by familiar comparisons are often
worse than useless. Any of the above examples will show that the first
result of explanation is not to make a phenomenon seem familiar, but to
put (as the saying is) 'quite a new face upon it.' When, indeed, we have
thought it over in all its newly discovered relations, we feel more at
home with it than ever; and this is one source of our satisfaction in
explaining things; and hence to substitute immediate familiarisation for
radical explanation, is the easily besetting sin of human understanding:
the most plausible of fallacies, the most attractive, the most difficult
to avoid even when we are on our guard agains