d: "I think,
therefore I am." Thus I am metaphysically established, and I throw upon
the doubters the burden of proving my non-existence. When we consider
how little has been found out about the mind, is it not amazing that any
one should presume to define what one can know or cannot know? I admit
that there are innumerable marvels in the visible universe unguessed by
me. Likewise, O confident critic, there are a myriad sensations
perceived by me of which you do not dream.

Necessity gives to the eye a precious power of seeing, and in the same
way it gives a precious power of feeling to the whole body. Sometimes it
seems as if the very substance of my flesh were so many eyes looking out
at will upon a world new created every day. The silence and darkness
which are said to shut me in, open my door most hospitably to countless
sensations that distract, inform, admonish, and amuse. With my three
trusty guides, touch, smell, and taste, I make many excursions into the
borderland of experience which is in sight of the city of Light. Nature
accommodates itself to every man's necessity. If the eye is maimed, so
that it does not see the beauteous face of day, the touch becomes more
poignant and discriminating. Nature proceeds through practice to
strengthen and augment the remaining senses. For this reason the blind
often hear with greater ease and distinctness than other people. The
sense of smell becomes almost a new faculty to penetrate the tangle and
vagueness of things. Thus, according to an immutable law, the senses
assist and reinforce one another.

It is not for me to say whether we see best with the hand or the eye. I
only know that the world I see with my fingers is alive, ruddy, and
satisfying. Touch brings the blind many sweet certainties which our more
fortunate fellows miss, because their sense of touch is uncultivated.
When they look at things, they put their hands in their pockets. No
doubt that is one reason why their knowledge is often so vague,
inaccurate, and useless. It is probable, too, that our knowledge of
phenomena beyond the reach of the hand is equally imperfect. But, at all
events, we behold them through a golden mist of fantasy.

There is nothing, however, misty or uncertain about what we can touch.
Through the sense of touch I know the faces of friends, the illimitable
variety of straight and curved lines, all surfaces, the exuberance of
the soil, the delicate shapes of flowers, the noble forms of