For 10 points, identify this economist who wrote Principles of Political Economy and Taxation and advanced the "iron law of wages."
He defended Say's law by arguing against the possibility of general gluts, and he called for a stable monetary policy in Proposals for an Economic and Secure Currency.  A concept developed by Robert Barro which states that equilibrium consumption is invariant if the government is financed by tax increases or deficit spending is known as his "equivalence," and he also introduced diminishing marginal returns. In another work, he criticized Malthus' theory of rent, and that work also introduced the theory of comparative advantage.  For 10 points, identify this economist who wrote Principles of Political Economy and Taxation and advanced the "iron law of wages."
He defended Say's law by arguing against the possibility of general gluts, and he called for a stable monetary policy in Proposals for an Economic and Secure Currency.  
David Ricardo