There is a sort of land which receives in autumn, year by year, the
deposit of its own dead leaves and weeds and grasses without either
the winds and waters to clear these away or the soil to reabsorb
and reconvert them into the materials of reproduction. Thus year by
year the land tends farther toward sterility by the very
accumulation of what was once its life. But send a forest fire
across those smothering strata of vegetable decay; give once more a
chance for every root below to meet the sun above; for every seed
above to reach the ground below; soon again the barren will be the
fertile, the desert blossom as the rose. It is so with the human
mind. It is ever putting forth a thousand things which are the
expression of its life for a brief season. These myriads of things
mature, ripen, bear their fruit, fall back dead upon the soil of
the mind itself. That mind may be the mind of an individual; it may
be the mind of a century, a race, a civilization. To the
individual, then, to a race, a civilization, a century, arrives the
hour when it must either consume its own dead or surrender its own
life. These hours are the moral, the intellectual revolutions of
history.

The new science must not only clear the stagnant ground for the
growth of new ideas, it must go deeper. Not enough that rubbish
should be burned: old structures of knowledge and faith, dangerous,
tottering, unfit to be inhabited longer, must be shaken to their
foundations. It brought on therefore a period of intellectual
upheaval and of drift, such as was once passed through by the
planet itself. What had long stood locked and immovable began to
move; what had been high sank out of sight; what had been low was
lifted. The mental hearing, listening as an ear placed amid still
mountains, could gather into itself from afar the slip and fall of