Does the agriculturist make his own clothes? Does the tailor produce the grain which he consumes? Does not your housekeeper cease to make her bread at home, as soon as she finds it more economical to buy it from the baker? Do you lay down your pen to take up the blacking-brush in order to avoid paying tribute to the shoe-black? Does not the whole economy of society depend upon a separation of occupations, a division of labor, in a word, upon mutual exchange of production, by which we, one and all, make a calculation which causes us to discontinue direct production, when indirect acquisition offers us a saving of time and labor. You are not then sustained by _practice_, since it would be impossible, were you to search the world, to show us a single man who acts according to your principle. You may answer that you never intended to make your principle the rule of individual relations. You confess that it would thus destroy all social ties, and force men to the isolated life of snails. You only contend that it governs _in fact_, the relations which are established between the agglomerations of the human family. We say that this assertion too is erroneous. A family, a town, county, department, province, all are so many agglomerations, which, without any exception, all _practically_ reject your principle; never, indeed, even think of it. Each of these procures by barter, what would be more expensively procured by production. Nations would do the same, did you not _by force_ prevent them. We, then, are the men who are guided by practice and experience. For to combat the interdict which you have specially put upon some international exchanges, we bring forward the practice and experience of all individuals, and of all agglomerations of individuals, whose acts being voluntary, render them proper to be given as proof in the question. But you, on your part, begin by _forcing_, by _hindering_, and then, adducing forced or forbidden acts, you exclaim: "Look; we can prove ourselves justified by example!" You exclaim against our _theory_, and even against _all theory_. But are you certain, in laying down your principles, so antagonistic to ours, that you too are not building up theories? Truly, you too have your theory; but between yours and ours there is this difference: