be proved by collecting examples and trusting vaguely to
the Uniformity of Nature. If no exceptions are found, we have an
empirical law of considerable probability within the range of our
exploration. If exceptions occur, we have at most an approximate
generalisation, as that 'Most metals are whitish,' or 'Most domestic
cats are tabbies' (but this probably is the ancestral colouring). We may
then resort to statistics for greater definiteness, and find that in
Hampshire (say) 90 _per cent._ of the domestic cats are tabby.

Sec. 5. Scientific Explanation consists in discovering, deducing, and
assimilating the laws of phenomena; it is the analysis of that
Heracleitan 'flux' which so many philosophers have regarded as
intractable to human inquiry. In the ordinary use of the word,
'explanation' means the satisfying a man's understanding; and what may
serve this purpose depends partly upon the natural soundness of his
understanding, and partly on his education; but it is always at last an
appeal to the primary functions of cognition, discrimination and
assimilation.

Generally, what we are accustomed to seems to need no explanation,
unless our curiosity is particularly directed to it. That boys climb
trees and throw stones, and that men go fox-hunting, may easily pass for
matters of course. If any one is so exacting as to ask the reason, there
is a ready answer in the 'need of exercise.' But this will not explain
the peculiar zest of those exercises, which is something quite different
from our feelings whilst swinging dumb-bells or tramping the highway.
Others, more sophisticated, tell us that the civilised individual
retains in his nature the instincts of his remote ancestors, and that
these assert themselves at stages of his growth corresponding with
ancestral periods of culture or savagery: so that if we delight to climb
trees, throw stones, and hunt, it is because our forefathers once lived
in trees, had no missiles but stones, and depended for a livelihood
upon killing something. To some of us, again, this seems an
explanation; to others it merely gives annoyance, as a superfluous
hypothesis, the fruit of a wanton imagination and too much leisure.

However, what we are not accustomed to immediately excites curiosity. If
it were exceptional to climb trees, throw stones, ride after foxes,
whoever did such things would be viewed with suspicion. An eclipse, a
shooting star, a solitary boulder on the heath, a strange anima