income. In so doing he started, implicitly, to impose a production boundary, including within it only money spent on the production of ‘Food, Housing, Cloaths, and all other necessaries’.8 All other ‘unnecessary expenses’, as defined by Petty, were omitted. In this way, by extension, Petty came to see any branch of the economy that did not produce those necessities as unproductive, adding nothing to national income.
