Here, we argue for a mathematical equation that captures desert. Our procedure consists of setting out principles that a correct equation must satisfy and then arguing that our set of equations satisfies them. We then consider two objections to the equation. First, an objector might argue that desert and well-being separately contribute to intrinsic goodness, and they do not separately contribute. The concern here is that our equations treat them as separate contributors. Second, our set of desert-equations are unlike equations (...) in science because our equations involve multiple desert-equations with the applicable equation depending on how the variables are filled out. Neither objection succeeds. (shrink)