Theological discourse on sacraments has tended to consider the sacramental subject as isolated individual and 'patient' of sacerdotal action. Yet, sacramental signification and sacramental e=icacy are ineluctably and undeniably intersubjective and social. This is because the sacramental actors themselves contribute to sacramental symbolism, not as individual participants in particular sacramental actions, but as members of the ecclesial 'body of action' (Copus Mysticum), contributors to the whole sacramental economy in history. Similarly, what sacraments e=ect is never a matter for isolated individuals, abstracted from concrete actuality, but always impinges on this ecclesial body as a whole, whether in terms of supernatural grace or natural social cohesion. As sacramental action is intersubjective, involving minister and recipient, so it is social in both its signification and e=ects. To consider the abstract individual to the exclusion of the concrete ecclesial body is to minimize what sacramental action means and does. Maurice Blondel's Action (1893) provides a rehabilitation of sacramental practice on a philosophical footing that instructs theology to remain open to the intersubjective and social aspects of sacramental action. In Blondel, we never act alone. All action is coaction. The 'exergy' of action emanating from the individual subject draws on the 'allergy' of action from other subjects: "Voluntary action is … the bond that builds up the city of man; it is the social function par excellence."1 The human subject belongs to various groups as unions of subjects, as social federation, that are principles of action in themselves. Transposing these insights into theology, and considering sacraments as human action in Blondel's terms, therefore, allows theology to remain open both to the intersubjectivity of sacramental action and its power for social cohesion.