In monetary matters, especially on the question of interest, the Physiocrats were willing to recognize an exception to their principle of non-intervention. Mirabeau thought that whenever a real increase of wealth resulted from the use of capital, as in agriculture, the payment of interest was only just. It was simply a sign or symbol of the net product. But in trade matters he thought it best to limit if not to prohibit it altogether. It often proved very harmful, and frequently was nothing better than a tax levied by order of “the corrosive landowners.” Quesnay could not justify it except in those cases where it yielded a net product, but he was content simply to suggest a limitation of it. The Physiocrats are at least logical. If capital sunk in industrial and commercial undertakings yields no income it is evident that the interest must be taken from the borrower’s pocket, and they condemned it just as they condemned taxing the industrial and commercial classes. Turgot[77] is the only one of them who frankly justifies taking interest. The reason that he gives is not the usual Physiocratic argument, but rather that the owner of capital may either invest it in the land or undertake some other productive work—capital being the indispensable basis of all enterprise[78]—and that, consequently, the capital will never be given to anyone who will offer less than what might have been made out of it did the owner himself employ it. This argument implies that every undertaking is essentially a productive one, and indeed one of the traits which distinguishes Turgot from the other Physiocrats is the fact that he did not think that industry and commerce were entirely unproductive. II: THE FUNCTIONS OF THE STATE Seeing that the Physiocrats believed that human society was pervaded by the principle of “natural order,” which required no adventitious aid from any written law, and since Nature’s voice, without any artificial restraint, was sufficient guide for mankind, it might have been expected that the trend of Physiocracy would have been toward the negation of all legislation, of all authority—in a word, toward the subversion of the State.