by the Sandwichman,
"This crime called blasphemy was invented by priests for the purpose of defending doctrines not able to take care of themselves." - Robert Green Ingersoll.
"To compel an employer to hire men for only eight hours and to compel the employe [sic] to work no longer than eight hours is certainly un-American." - David McLean Parry.
Consider a single individual with a utility function U (y, ℓ ) where y is income and ℓ is leisure. Both y and ℓ are 'goods', i.e. the consumer prefers more of each.
Suppose this person has non-labor income of G, and can work as many hours, h, as she wishes at a wage of w per hour. Total time available for the only two possible activities, work (h) and leisure (ℓ) is T.
If she allocates her time between work and leisure to maximize her utility, what can we say about her decisions, and about how these decisions will respond to changes in the exogenous parameters, w and G?
1. In what sense can w and G be said to be "exogenous"?
2. Defend the proposition that an individual "can work as many hours as she wishes at a wage of w per hour."
3. In what way does the supposition of the static labor supply model that individuals are free to work as many (or few) hours as they wish differ from the Parry doctrine that regulation of the hours of work by law is "un-American"?
To assume that wages are "exogenous" to the number of hours worked is to assume either that there is no effect on productivity from variation in hours or that there is no effect on wages from variation in productivity. Those assumption are not mere convenient simplifications but rather egregiously violate core principles of marginalist analysis.
"Suppose that supply has no effect on price and that price has no effect on demand." What kind of "economic model" could one construct based on that statement? That is the level of incoherence exhibited by the static labor supply model.
The blasphemy committed by advocates of shorter working time is not -- as claimed by economists -- an assumption that there is a fixed amount of work to be done regardless of the cost of labor. The blasphemous assumption of shorter work time advocates is that individuals are not free to work as many or as few hours as they wish at a given wage. Their crime is thus not committing a fallacy but refusing to be conned by one.