A treatise has without doubt an incontestable superiority. But it requires to be read, meditated, and understood. It addresses itself to the select few. Its mission is first to fix attention, and then to enlarge the circle of acquired knowledge.

A work that undertakes the refutation of vulgar prejudices cannot have so high an aim. It aspires only to clear the way for the steps of Truth; to prepare the minds of men to receive her; to rectify public opinion, and to snatch from unworthy hands dangerous weapons they misuse.

It is above all in social economy that this hand-to-hand struggle, this ever-reviving combat with popular errors, has as true practical utility.