. For we are still in the early
morning of scientific discovery: the dawn of the modern period, faintly
heralded by Copernicus, brought nearer by the work of Tycho and Kepler,
and introduced by the discoveries of Galileo--the dawn has occurred, but
the sun is not yet visible. It is hidden by the clouds and mists of the
long night of ignorance and prejudice. The light is sufficient, indeed,
to render these earth-born vapours more visible: it is not sufficient to
dispel them. A generation of slow and doubtful progress must pass,
before the first ray of sunlight can break through the eastern clouds
and the full orb of day itself appear.

It is this period of hesitating progress and slow leavening of men's
ideas that we have to pass through in this week's lecture. It always
happens thus: the assimilation of great and new ideas is always a slow
and gradual process: there is no haste either here or in any other
department of Nature. _Die Zeit ist unendlich lang._ Steadily the forces
work, sometimes seeming to accomplish nothing; sometimes even the
motion appears retrograde; but in the long run the destined end is
reached, and the course, whether of a planet or of men's thoughts about
the universe, is permanently altered. Then, the controversy was about
the _earth's_ place in the universe; now, if there be any controversy of
the same kind, it is about _man's_ place in the universe; but the
process is the same: a startling statement by a great genius or prophet,
general disbelief, and, it may be, an attitude of hostility, gradual
acceptance by a few, slow spreading among the many, ending in universal
acceptance and faith often as unquestioning and unreasoning as the old
state of unfaith had been. Now the process is comparatively speedy:
twenty years accomplishes a great deal: then it was tediously slow, and
a century seemed to accomplish very little. Periodical literature may be
responsible for some waste of time, but it certainly assists the rapid
spread of ideas. The rate with which ideas are assimilated by the
general public cannot even now be considered excessive, but how much
faster it is than it was a few centuries ago may be illustrated by the
attitude of the public to Darwinism now, twenty-five years after _The
Origin of Species_, as compared with their attitude to the Copernican
system a century after _De Revolutionibus_. By the way, it is, I know,
presumptuous for me to have an opinion, but I cannot hear Darwin
compar