their differences, however, both a cash-flow consumption tax and an SHS tax require that dollars paid out as business or investment expenses be eliminated from the base. This is necessary under a cash-flow consumption tax because business and investment expenses are not consumption and it is necessary under an SHS tax because these expenditures are neither consumption nor additions to savings. Since business and investment outlays have no place in the base of either tax, intuition suggests that business and investment interest expenses would be treated identically under a cash-flow consumption tax and an SHS tax. But they are not. The SHS tax and the cash-flow consumption tax take different structural approaches to the treatment of business and investment interest outlays although both systems share the general objective of removing current business and investment costs from the tax base. Tax on Haig–Simons income Tax on change in wealth The Haig–Simons equation is different from the USA's individual income tax base calculations. For example, any employer contributions to employee health insurance are not included in taxable employee income. Under the Haig–Simons definition of income, such contributions would be included in income. Such contributions might not be included in a Haig–Simons income tax base, however, if their exclusion reflected "an appropriate adjustment in measuring ability to pay." Tax on consumption The European Union and most states in the USA employ a tax on Haig–Simons income with a consumption tax. In the European Union, a value added tax applies to purchases of goods and services on each level of exchange until it reaches the ultimate consumer. In the US, most states tax purchases of goods with a sales tax. Criticisms of the definition Some argue that the definition is tautological: it is "little more than an accounting identity, a tautology: it tells us only that all income is either spent [consumption] or not [savings], which is obvious enough". Others observe that it is "only a surrogate utility measure." Some fault it for neutrality between savings and consumption. Some scholars resist these criticisms, to the extent they conceive of Haig–Simons as dependent on utility; Simons rejected utility as the basis of the ability-to-pay standard. Indeed, Simons rejected both the notion that humans are "equally efficient pleasure machines," and the idea that taxation can take account of interpersonal utilities. Simons sought a measurable definition for income, but his solution is open to criticism for reifying