However plausible, at first sight, the intervention of the State might be, it was soon perceived that it is always oppressive to one or other of the contracting parties.

When we look into these subjects, we are always compelled to reason upon this maxim, that _equal value_ results from liberty.

We have, in fact, no other means of knowing whether, at a given moment, two services are of the same value, but that of examining whether they can be readily and freely exchanged.

Allow the State, which is the same thing as force, to interfere on one side or the other, and from that moment all the means of appreciation will be complicated and entangled, instead of becoming clear.

It ought to be the part of the State to prevent, and, above all, to repress artifice and fraud; that is, to secure liberty, and not to violate it.