This chapter reconstructs the environment in which the verb to be will be understood in a new way. It identifies three radical changes, conceptually distinct but not completely unrelated, that come into play when looking at language from the structuralist perspective. First, if what matters are the relationships, elements that have the same relationships to other elements of the system must be considered equivalent and, in principle, they can be exchanged (the commutation principle). Second, given an incompletely filled grid that combines certain properties, if the grid is correct, it will lead to the discovery of new objects that could fill the empty grid spaces (the retrieval principle). Third, not all possible combinations of primitive elements are used in every language (the redundancy principle).