Wrigley 1

Classical economic view:

What are the limits on an organic economy?

A similar argument for energy

Incomes tend to return to the subsistence minimum (enough only for minimum food, shelter, clothing and fuel), therefore little demand for comforts and luxuries
the percentage of income an average family spends on food approximates the percentage of workers in agriculture (because if families spend 75% of their income on food then there isn't a market for workers to make other things)

Wrigley's key argument:
it wouldn't be possible to have sustained economic growth without dramatically increased use of inorganic sources of energy