It may be well to explain in a word to the general reader that this sect were patriots and practical social and political reformers quite as much as theoretical economists.  They believed the condition of the French people to have grown so bad as to be a grave danger to the State, and they preached their system as a revelation of the only way of salvation.  They were too earnest for the Paris wits.  Voltaire always sneered at them till he came to know Turgot.  Grimm calls them “the pietists of philosophy,” and Hume, bantering Morellet, wonders how a man like Turgot could herd with such cattle, “the most chimerical and the most arrogant that now exist since the annihilation of the Sorbonne.”  But they were grappling with living problems, and seeing into the real situation so much further than their contemporaries, that an historian like de Tocqueville thinks the best key to the Revolution is to be found in their writings.  The malady of the age, they held, was the ever-increasing distress of the agricultural population.  The great nobles, the financiers, the farmers-general, the monopolists, were very rich; but the agriculturists—­the vast body of the people—­were sinking into a hopeless impoverishment, for between tithes and heavy war taxes and farmer-generals’ extortions, and the high rents which, to Turgot’s despair, the smaller peasantry would persist in offering without reflecting in the least on the rise in their burdens,—­between all these things, the net product of agriculture—­what was left in the hands of the cultivator after all expenses were paid away—­was getting less and less every year, and the ruin of the peasantry meant the ruin of the nation.  “Poor peasants, poor kingdom,” said they; “poor kingdom, poor king.”

And the remedy was plain:  the net product of agriculture must somehow be made to rise instead of fall.  They supported their contention with a certain erroneous theory that agriculture is the sole source of wealth, but the error made little practical difference to the argument, for agriculture is always a sufficiently important source of wealth to make its improvement a national concern.  How then was the net product to be increased?  By better methods of cultivation, by removal of legal and official interferences, and by lightening the public burdens through the abolition of all existing taxes and of the existing system of collecting them through farmers-general, and the institution instead of a single tax on the net product of the soil, to be collected directly by responsible officials.  According to the reminiscences of strangers who happened to fall into their company, the talk of the economists always ran much on the net product and the single tax, for they believed the two great needs of the country were agricultural improvement and financial reform.  When Quesnay was offered a farmer-generalship of the taxes for his son, he said, “No; let the welfare of my children be bound up with the public prosperity,” and made his son a farmer of the land instead.