The GENERAL CONTEXT of such use is:
identifying possible relationships for school systems: Every school system, to varying degrees and in forms determined in each case by the structure of class relations, fulfills the totality of the functions corresponding to the totality of the possible relationships with the other systems, so that its structure and functioning are always organized in relation to a determinate struction of possible functions. Constructing the system of possible configurations of the system of functions would be a purely academic exercise if it did not enable each historical case to be treated as a particular case of the ideal totality of the possible combinations of functions, thereby bringing to light all the relations between the school system and the other sub-systems, not least, of course, the blank or negative relations which are, by definition, the best-hidden ones.