 Hayley Clatterbuck, Elliott Sober, and Richard Lewontin (2013) argue that it doesn’t make sense to talk of drift “dominating” selection or being “stronger than” selection. (Among many such claims, this would challenge Dietrich and Millstein’s (2008) claim, discussed in the previous section, that the best way to understand the nearly neutral theory is as weak selection dominated by drift). Clatterbuck, Sober, and Lewontin take selection and drift to be a population-level process or processes (they don’t take a stand on whether there is a one process or two, but they are clearly “causalists” rather than “statisticalists”), but they raise concerns for the way that biologists have understood the value \(Ns\), which is the effective size of the population multiplied by the selection coefficient. After some initial controversies over how to interpret this value, most biologists eventually came to the view that