transaction to which the plane gave occasion. The transaction cannot be
accomplished without the consent of the one as well as of the other. The
worst which can happen is, that James may be too exacting; and in this
case, William, refusing the loan, remains as he was before. By the fact
of his agreeing to borrow, he proves that he considers it an advantage
to himself; he proves, that after every calculation, including the
remuneration, whatever it may be, required of him, he still finds it
more profitable to borrow than not to borrow. He only determines to do
so because he has compared the inconveniences with the advantages. He
has calculated that the day on which he returns the plane, accompanied
by the remuneration agreed upon, he will have effected more work, with
the same labour, thanks to this tool. A profit will remain to him,
otherwise he would not have borrowed. The two services of which we are
speaking are exchanged according to the law which governs all exchanges,
the law of supply and demand. The claims of James have a natural and
impassable limit. This is the point in which the remuneration demanded
by him would absorb all the advantage which William might find in making
use of a plane. In this case, the borrowing would not take place.
William would be bound either to make a plane for himself, or to do
without one, which would leave him in his original condition. He
borrows, because he gains by borrowing. I know very well what will be
told me. You will say, William may be deceived, or, perhaps, he may be
governed by necessity, and be obliged to submit to a harsh law.

It may be so. As to errors in calculation, they belong to the infirmity
of our nature, and to argue from this against the transaction in
question, is objecting the possibility of loss in all imaginable
transactions, in every human act. Error is an accidental fact, which is
incessantly remedied by experience. In short, everybody must guard
against it. As far as those hard necessities are concerned, which force