We should keep these data in mind when evaluating utopian schemes. Theists and postmodernist critics of science often label the disastrous Soviet and Nazi utopias as “scientific.” But science was a thin patina covering a deep layer of counter-Enlightenment pastoral paradisiacal fantasies of racial ideology grounded in blood and soil, as documented in Claudia Koonz's 2003 book The Nazi Conscience (Belknap Press) and in Ben Kiernan's 2007 book Blood and Soil (Yale University Press). Such utopias can rack up high body counts with a utilitarian calculus in which everyone is presumed to be happy forever. As Harvard psychologist Steven Pinker explains in The Better Angels of Our Nature (Viking, 2011), people who oppose a utopia “are the only things standing in the way of a plan that could lead to infinite goodness. How evil are they? You do the math.”