Abstract : The paper shows the importance of the lability phenomena on digital productions, making ineffective the preservation solutions used by museums to preserve digital installations. It then proposes an alternative based on an ontological model coming from the ontological conception of Spinoza interpreted by Deleuze. The article shows that this ontology is compatible with the communication created by the work. This model leads to a definition of the work as a power to act. This model is finally used to design an indexing tool of works.