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.
Gurwitsch, A. (2010). Ontological problems, in The collected works of Aron Gurwitsch (1901-1973) III, Dordrecht, Springer, pp. 369-402.
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