of the more-crude opinions, and so far from religious feeling
having been weakened by their perennial series of victories, it
has apparently been growing deeper and stronger all the time. The
religious sense is as yet too feebly developed in most of us; but
certainly in no preceding age have men taken up the work of life
with more earnestness or with more real faith in the unseen than
at the present day, when so much of what was once deemed
all-important knowledge has been consigned to the limbo of
mythology.

The more-crude theories of early times are to be chiefly
distinguished from the less-crude theories of to-day as being
largely the products of random guesswork. Hypothesis, or
guesswork, indeed, lies at the foundation of all scientific
knowledge. The riddle of the universe, like less important
riddles, is unravelled only by approximative trials, and the most
brilliant discoverers have usually been the bravest guessers.
Kepler's laws were the result of indefatigable guessing, and so,
in a somewhat different sense, was the wave-theory of light. But
the guesswork of scientific inquirers is very different now from
what it was in older times. In the first place, we have slowly
learned that a guess must be verified before it can be accepted
as a sound theory; and, secondly, so many truths have been
established beyond contravention, that the latitude for
hypothesis is much less than it once was. Nine tenths of the
guesses which might have occurred to a mediaeval philosopher
would now be ruled out as inadmissible, because they would not
harmonize with the knowledge which has been acquired since the
Middle Ages. There is one direction especially in which this
continuous limitation of guesswork by ever-accumulating