 Both the effort and productive contribution theories rely on concepts that invite further specification. Consider the concept of marginal product. What is produced by one’s efforts depends on the productivity of the tools and raw materials one has at one’s disposal. The state is a contributing participant, also, in every cooperative exchange (B. Fried 1995). Given that many people make interdependent contributions to social product, the link between any individual’s labor and output seems too attenuated to ground anything more determinate than the claim that people deserve something based on what they produce (Scanlon 2018: ch8). And it is hard to see how so general a normative claim could bear the weight of justifying any precise proposal for surplus division.