other notion. He is aware, again, that a man cannot see his own
face, though he can touch it. Sight, then, he concludes, is a sort of
touch, which only extends to objects different from our own visage, and
remote from us. Now touch only conveys to him the idea of relief. A
mirror, therefore, must be a machine which sets us in relief out of
ourselves. How many philosophers, cries Diderot, have employed less
subtlety to reach notions just as untrue?

The born-blind had a memory for sound in a surprising degree, and
countenances do not present more diversity to us than he observed in
voices. The voice has for such persons an infinite number of delicate
shades that escape us, because we have not the same reason for
attention that the blind have. The help that our senses lend to one
another, is an obstacle to their perfection.

The blind man said he should have been tempted to regard persons endowed
with sight as superior intelligences, if he had not found out a hundred
times how inferior we are in other respects. How do we know--Diderot
reflects upon this--that all the animals do not reason in the same way,
and look upon themselves as our equals or superiors, notwithstanding our
more complex and efficient intelligence? They may accord to us a reason
with which we should still have much need of their instinct while they
claim to be endowed with an instinct which enables them to do very well
without our reason.

When asked whether he should be glad to have sight, the born-blind
replied that, apart from curiosity, he would be just as well pleased to
have long arms: his hands would tell him what is going on in the moon,
better than our eyes or telescopes; and the eyes cease to see earlier
than the hands lose the sense of touch. It would therefore be just as
good to perfect in him the organ that he had, as to confer upon him
another which he had not. This is untrue. No conceivable perfection of
touch would reveal phenomena of light, and the longest arms must leave
those phenomena undisclosed.

After recounting various other peculiarities of thought, Diderot notices
that the blind man attaches slight importance to the sense of shame. He
would hardly understand the utility of clothes, for instance, except as
a protection against cold. He frankly told his philosophising visitors
that he could not see why one part of the body should be covered rather
than another. "I have never doubted," says Diderot, "that the state of
our orga