• I have endeavoured to show that the ability to pay taxes depends, not on the gross money value of the mass of commodities, nor on the net money value of the revenue of capitalists and landlords, but on the money value of each man's revenue compared to the money value of the commodities which he usually consumes.

    David Ricardo, John Ramsay McCulloch (1852). “The Works of David Ricardo. With a notice of the life and writings of the author: by J. R. McCulloch”, p.7