 Peter Godfrey-Smith (2009) characterizes drift as changes where two parameters, the smoothness of fitness landscapes and dependence of reproductive character on fitness differences, are low. (However, when he needs to explicate why drift has special importance in small populations and why it can be mathematically described in particular ways, he appeals to indiscriminate sampling. Perhaps, then, indiscriminate sampling is at the core of Godfrey-Smith’s view of drift).