そしてわたし自身，今までにただ一人の師しか持たなかったなら，あるいは，どんなにすぐれた学者たちの意見にもつねに相違があったことを知らなかったなら，疑いなく第二の部類に入っていただろう。けれども，学院にいたころから，どんなに風変わりで信じがたいことを想像しようとも，哲学者たちのだれかによって言われなかったようなことは一つもないのを学び知った。またその後，旅をして，次のことを認めていった。わたしたちとまったく反対の意見をもつすべての人が，それゆえに野蛮で未開だというわけでなく，それどころか，多くの人がわたしたちと同じかそれ以上に，理性を働かせていることだ。そして考えた。同じ精神を具えた同じ一人の人間でも，子供の時からフランス人やドイツ人のあいだで育てられると，中国人や人食い人種のなかでずっと生活してきたのとは，どんなに違った人間になることか。そしてわたしたちの服装の流行においてまで，十年前に気に入っていて，また十年もしないうちに気に入るかもしれない同じものが，今どれほど突飛でこっけいに見えることか。結局のところ，習慣や実例のほうが，どんな確実な知識よりもわたしたちを納得させているが，それにもかかわらず，少しでも発見しにくい真理については，ただ一人の人がそういう真理を見つけだしたというほうが，国中の人が見つけだしたというより，はるかに真らしいから，賛成の数が多いといっても何ひとつ価値のある証拠にはならない。こうしてわたしは，他の人よりもこの人の意見のほうを探るべきだと思われる人を選び出すことができずに，自分で自分を導いていかざるをえないことになっていた。
For my own part, I should doubtless have
belonged to the latter class, had I received
instruction from but one master, or had I
never known the diversities of opinion that
from time immemorial have prevailed among
men of the greatest learning. But I had become
aware, even so early as during my college
life, that no opinion, however absurd and
incredible, can be imagined, which has not
been maintained by some one of the philosophers;
and afterwards in the course of my travels
I remarked that all those whose opinions
are decidedly repugnant to ours are not on
that account barbarians and savages, but
on the contrary that many of these nations
make an equally good, if not a better, use
of their Reason than we do. I took into account
also the very different character which a
person brought up from infancy in France
or Germany exhibits, from that which, with
the same mind originally, this individual
would have possessed had he lived always
among the Chinese or with savages, and the
circumstance that in dress itself the fashion
which pleased us ten years ago, and which
may again, perhaps, be received into favour
before ten years have gone, appears to us
at this moment extravagant and ridiculous.
I was thus led to infer that the ground of
our opinions is far more custom and example
than any certain knowledge. And, finally,
although such be the ground of our opinions,
I remarked that a plurality of suffrages
is no guarantee of truth where it is at all
of difficult discovery, as in such cases
it is much more likely that it will be found
by one than by many. I could, however, select
from the crowd no one whose opinions seemed
worthy or preference, and thus I found myself
constrained, as it were, to use my own Reason
in the conduct of my life.