 Beyond that core idea, particular basic income schemes differ considerably; not least concerning the level at which the basic income is to be paid. To help calibrate alternatives, Van Parijs suggests that an amount corresponding to a quarter of current GDP per capita—which, in 2015, would have corresponded to $1163 per month in the United States—would sit between “modest” and “generous” versions of the idea (Van Parijs &amp; Vanderborght 2017: 11).