that he does not observe an evident mental distinction.
It cannot be true that there is nothing abiding in what we know.
For if that were so we should not know it all and should not call
it knowledge. Our mental state may be very different from that
of somebody else some thousands of years back; but it cannot be
entirely different, or else we should not be conscious of a difference.
Mr. Wells must surely realize the first and simplest of the paradoxes
that sit by the springs of truth. He must surely see that the fact
of two things being different implies that they are similar.
The hare and the tortoise may differ in the quality of swiftness,
but they must agree in the quality of motion. The swiftest hare
cannot be swifter than an isosceles triangle or the idea of pinkness.
When we say the hare moves faster, we say that the tortoise moves.
And when we say of a thing that it moves, we say, without need
of other words, that there are things that do not move.
And even in the act of saying that things change, we say that there
is something unchangeable.

But certainly the best example of Mr. Wells's fallacy can be
found in the example which he himself chooses. It is quite true
that we see a dim light which, compared with a darker thing,
is light, but which, compared with a stronger light, is darkness.
But the quality of light remains the same thing, or else we
should not call it a stronger light or recognize it as such.
If the character of light were not fixed in the mind, we should be
quite as likely to call a denser shadow a stronger light, or vice
versa If the character of light became even for an instant unfixed,
if it became even by a hair's-breadth doubtful, if, for example,
there crept into our idea of light some vague idea of blueness,
then in that flash we have become doubtful whether the new light