The theme-thematic-field structure is a formal invariant of organization having universal significance. The structure is realized at every moment of conscious life, whatever object (in the broadest sense of the term) presents itself through a given act. As every formal invariant assumes a specific form in every concrete variety in which it is embodied, so is relevancy specified in every case in which a theme appears in a thematic field. As actually experienced, relevancy is always qualified and specified in accordance with, and in dependence upon, the material contents of both the theme and the thematic field.