But when, changing the noun into an adjective, they alter the phrase, thus, "The land is a productive instrument," they make a wicked blunder.
According to Quesnay and the early economists, all production comes from the land.

Smith, Ricardo, and de Tracy, on the contrary, say that labor is the sole agent of production.

Say, and most of his successors, teach that BOTH land AND labor AND capital are productive.

The latter constitute the eclectic school of political economy.

The truth is, that NEITHER land NOR labor NOR capital is productive.