In the present paper, the concept of incommensurability is analyzed in the light of what is happening in different disciplines related to psychology. It is detected that there are many concepts that are applied in different studies without a conceptual elaboration or re-elaboration from new attributes identified in a certain phenomenon. Sometimes it consists of merely adding together many terms; in other cases, concepts are transferred without specifying the ontology or taxonomy of which they are part. Two theoretical works are described - one by Castorina and the other one by Bruner - to exemplify the arguments expressed. Finally, it is argued that a certain margin of common space would exist between psychological theories, which could be represented, for example, in the resolution of "problems" (both theoretical and empirical). That is to say, a theory is valid while it is questionned by an important sector of the scientific community (mainly for research and secondarily for professional practice).