The term revolution refers to the modifications of relationships between the child and his environment during his life. These relationships do not have a permanent status in that every level of organization can be considered both as a result or as a starting point. The thesis chosen in this article suggests that every organization of a given level constitutes the program for further revolutions. The programmed aspect of these revolutions does not lessen the role and necessity of interactions with the various environments. The sensory-motor period has been taken here as an example.