The article suggests the social dilemma way in order to cope with the problems of the relations between individual action and collective action in the field of environmental protection and recovery. This way, typical of the social sciences, holds the behaviour of free riding at the center of the analysis. Despite not explicitely followed by the papers presented at the seminar, the social dilemma could be useful to read some questions they raised: the nominalistic image of man; the commodification process of the planet; the prospect of industrial degrowth. The origin of this way dates back to the report of The Club of Rome of 1972 and to the release of F. Hirsch’s book in 1976. The most important contribution based on this approach remains the impressive collection of researches carried out by Elinor Ostrom and her
students on local and global common-pool resources (commons). According to Ostrom’s view, the regulation of commons is not exclusively a responsibility of the State (as argued by Hardin in his famous piece on the tragedy of commons ). The role of institutions is crucial, but these institution could also be of local or communitarian origin. The intelligibility of the human behaviour into this institutional framework will be facilitated by the adoption of «second-generation models of rationality».