 Mill can explain differential accomplishments in philosophy, science, and the arts by appeal to social barriers to women’s participation in these fields (313–18) and to competing domestic demands that are placed on them (318–19). In this connection, it is worth noting that Mill can concede not only differential accomplishments of the sexes but differential capacity, in at least one sense. For Mill can and should distinguish between actual capacity and potential capacity. Actual capacities determine what an agent is now able to do, whereas potential capacities determine what actual capacities she can develop. For instance, I have no actual capacity to speak Russian, but presumably I do have a potential capacity to speak Russian. By contrast, I don’t have even a potential capacity to fly or run a three-minute mile. Actual capacities are a function of potential capacities and suitable training, opportunities, and responsibilities. If I have not been given a proper education and training with suitable deliberative opportunities and responsibilities at various points in my development, my potential competence may not be actualized. Even if everyone had equal potential capacities, we should expect unequal actual capacities in systems where education and deliberative opportunities and responsibilities have been distributed unequally. If so, then greater actual capacity would not be evidence of greater potential capacity.