John Vorhaus explores the idea that people with people with profound and multiple learning difficulties (PMLD) are participants in a common life, or are potential participants in that life. There is a distinction between the capacity to do something, and the potential to develop a capacity. Two kinds of case illustrate the potential to participate on the part of people with PMLD: in the first, a trustee or surrogate acts as an intermediary between someone with PMLD and other persons or institutions. In the second case, a person with PMLD has the capacity to participate if she receives the skilled assistance of a parent, carer, or teacher. Generally, homes and schools for children with PMLD develop distinctive social environments as intricate and elaborate as in many other complex human organisations. The capacities of people with PMLD will themselves have a pervasive influence on norms of conduct and patterns of social interaction.