Quesnay’s approach to quantifying economic law makes his Economic Table possibly the first empirical macroeconomic model. The numbers in this Table were the result of a close study of the French economic system, giving them a firm empirical basis. This study indicated that farming technology was sufficient for farmers to generate a net surplus of at least 100 per cent. In our example, this is what they achieve – starting £2 million of corn, they receive this back plus a net surplus of £2 million, which is then paid in rent. Modern economists use these kinds of empirical results to think about the impact of policy change, and Quesnay used his Table for a similar purpose. He argued that if farmers had to pay too much tax, either directly or indirectly, they would cut back their capital investment in farming technology to thrive. This led the physiocrats to argue that there should be only one tax: on the rental value of land.