has more light or less. In brief, the progress may be as varying
as a cloud, but the direction must be as rigid as a French road.
North and South are relative in the sense that I am North of Bournemouth
and South of Spitzbergen. But if there be any doubt of the position
of the North Pole, there is in equal degree a doubt of whether I
am South of Spitzbergen at all. The absolute idea of light may be
practically unattainable. We may not be able to procure pure light.
We may not be able to get to the North Pole. But because the North
Pole is unattainable, it does not follow that it is indefinable.
And it is only because the North Pole is not indefinable that we
can make a satisfactory map of Brighton and Worthing.

In other words, Plato turned his face to truth but his back on
Mr. H. G. Wells, when he turned to his museum of specified ideals.
It is precisely here that Plato shows his sense. It is not true
that everything changes; the things that change are all the manifest
and material things. There is something that does not change;
and that is precisely the abstract quality, the invisible idea.
Mr. Wells says truly enough, that a thing which we have seen in one
connection as dark we may see in another connection as light.
But the thing common to both incidents is the mere idea of light--
which we have not seen at all. Mr. Wells might grow taller and taller
for unending aeons till his head was higher than the loneliest star.
I can imagine his writing a good novel about it. In that case
he would see the trees first as tall things and then as short things;
he would see the clouds first as high and then as low.
But there would remain with him through the ages in that starry
loneliness the idea of tallness; he would have in the awful spaces
for companion and comfort the definite conception that he was growing
taller and not (for instance) growing fatter.