In well known formulations, political science, classical and neoclassical economics, and political economy have recognized as foundational a human impulse toward self-preservation. To employ this concept, modern social-sciences theorists have made simplifying assumptions about human nature and have then built elaborately upon their more incisive simplifications. Advances in biology, including advances in evolutionary theory, notably inclusive-fitness theory, have for decades now encouraged the reconsideration of such assumptions and, more ambitiously, the reconciliation of the social and life sciences. I ask if this reconciliation is feasible and test a path to the unification of politics and biology, called here “political biology.” Two new notions, “fitness extraction” and “fitness exchange,” are defined, then differentiated from each other, and lastly contrasted to cooperative gaming, the putative essential element of economics.