An advisory note sent to the farmers of a block contains the four claims below. Which one could be settled by measurement rather than by argument about what is worth doing?

Two yields per hectare can be weighed on a scale and the note either matches the harvest records or does not. The other three tell the farmer what is wise, what he owes and what is foolish; each depends on how the costs and risks of farming are to be valued, and two farmers who accept the same yields may still part company over them.