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 organs and senses has much influence both on our metaphysics and our morality.”  This, I may observe, does not in the least show that in a society of human beings, not blind, but endowed with vision, the sense of physical shame is a mere prejudice of which philosophy will rid us.  The fact that a blind man discerns no ill in nakedness, has no bearing on the value or naturalness of shame among people with eyes.  And moreover, the fact that delicacy or shame is not a universal human impulse, but is established, and its scope defined, by a varying etiquette, does not in the least affect the utility or wisdom of such an artificial establishment and definition.  The grounds of delicacy, though connected with the senses, are fixed by considerations that spring from the social reason.  It seems to be true, as Diderot says, that the born-blind are at first without physical delicacy; because delicacy has its root in the consciousness that we are observed, while the born-blind are not conscious that they are observed.  It is found that one of the most important parts of their education is to impress this knowledge upon them.[66]