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communicate with and understand each other. It is not less evident
that man alone is endowed with reason, and that on this account he
is clearly distinguished from all the other productions of nature.

"However, were it not for the picture that so many celebrated men
have drawn of the weakness and lack of human reason; were it not
that, independently of all the freaks into which the passions of man
almost constantly allure him, the _ignorance_ which makes him the
opinionated slave of custom and the continual dupe of those who wish
to deceive him; were it not that his reason has led him into the
most revolting errors, since we actually see him so debase himself
as to worship animals, even the meanest, of addressing to them his
prayers, and of imploring their aid; were it not, I say, for these
considerations, should we feel authorized to raise any doubts as to
the excellence of this special light which is the attribute of man?

"An observation which has for a long time struck me is that, having
remarked that the habitual use and exercise of an organ
proportionally develops its size and functions, as the lack of
employment weakens in the same proportion its power, and even more
or less completely atrophies it, I am apprised that of all the
organs of man's body which is the most strongly submitted to this
influence, that is to say, in which the effects of exercise and of
habitual use are the most considerable, is it not the organ of
thought--in a word, is it not the brain of man?

"Compare the extraordinary difference existing in the degree of
intelligence of a man who rarely exercises his powers of thought,
who has always been accustomed to see but a small number of things,
only those related to his ordinary wants and to his limited desires;
who at no time thinks about these same objects, because he is
obliged to occupy himself incessantly with providing for these same
wants; finally, who has few ideas, because his attention,
continually fixed on the same things, makes him notice nothing, that
he makes no comparisons, that he is in the very heart of nature
without knowing it, that he looks upon it almost in the same way as
do the beasts, and that all that surrounds him is nothing to him:
compare, I say, the intelligence of this individual with that of the
man who, prepared at the outset by education, has contracted the
useful practice of exerci