does not know just as important as knowing what one does
know....

"The development of exact natural knowledge in all its vast range,
from physics to history and criticism, is the consequence of the
working out, in this province, of the resolution to 'take nothing
for truth without clear knowledge that it is such'; to consider all
beliefs open to criticism; to regard the value of authority as
neither greater nor less, than as much as it can prove itself to be
worth. The modern spirit is not the spirit 'which always denies,'
delighting only in destruction; still less is it that which builds
castles in the air rather than not construct; it is that spirit
which works and will work 'without haste and without rest,'
gathering harvest after harvest of truth into its barns, and
devouring error with unquenchable fire" (p. viii.).

The harvesting of truth is a safe enough enterprise, but the devouring
of error is a more dangerous pastime, since flames are liable to spread
beyond our control; and though, in a world overgrown with weeds and
refuse, the cleansing influence of fire is a necessity, it would be
cruel to apply the same agency again at a later stage, when a fresh
young crop is springing up in the cleared ground.

CHAPTER V

RELIGION AND PHILOSOPHY

The aphorism sometimes encountered, that "whatever properties appertain
to a whole must essentially belong to the parts of which it is
composed," is a fallacy. A property can be possessed by an aggregation
of atoms which no atom possesses in the slightest degree. Those who
think otherwise are unacquainted with mathematical laws other than
simple proportion or some continuous or additive functions; they are
not aware of discontinuities; they are not experienced in critical
values, above which certain conditions obtain, while below them there
is suddenly nothing. To refute them an instance must suffice:--

A meteoric stone may seem to differ from a planet only in size, but the
difference in size involves also many other differences, notably the
fact that the larger body can attract and hold to itself an
atmosphere--a circumstance of the utmost importance to the existence of
life on its surface. In order, however, that a planet may by
gravitative attraction control the roving atoms of gas, and confine
their excursions to within a certain range of itself, it must have a
very considerable mass.

The earth is big