theme. Themes are typical components of communication. They organize the memory of communication and tie together communicative contributions into complexes that belong together, so that it becomes recognizable in the developing communication, whether a theme is being maintained and developed, or is being changed.

In literature: A salient abstract idea that emerges from a literary work's treatment of its subject-matter; or a topic recurring in a number of literary works. While the subject of a work is described concretely in terms of its action (e.g. 'the adventures of a newcomer in the big city'), its theme or themes will be described in more abstract terms (e.g. love, war, revenge, betrayal, fate, etc.). The theme of a work may be announced explicitly, but more often it emerges indirectly through the recurrence of motifs. Adjective: thematic. [Baldick 1990]

In music: A theme is a complete tune or melody which is of fundamental importance in a piece of music. Thematic metamorphosis or thematic transformation describes a process used by Liszt and others in which a theme may undergo transformation to provide material to sustain other movements or sections of a work, where new and apparently unrelated themes might otherwise have been used. [Glossary of Musical Terms]

 

Luhmann:

But how can communication in general become a process? Here, too, a distinct, functionally specific difference, namely, the difference between themes and contributions, appears to act as a condition of possibility. Communicative nexes must be ordered by themes to which contributions can relate. Themes outlive contributions; they integrate different contributions into a longer-lasting, short-term or even long-term nexus of meaning. One can talk about some themes forever, and about others almost endlessly. Themes also regulate who can contribute what. They discriminate contributions and thereby contributors: for example, one requirement of sociable communication is selecting themes to which everyone present can contribute something, themes that do not tempt anyone to exhibit his individuality and that give each one the chance to make satisfying individual contribution in which he can be recognized.

The difference between themes and contributions is inadequately characterized as a "difference between levels." Themes and contributions regulate the possibility of negating content. On the one hand, there are thresholds of thematization, for example, in reference to obscenities, religious feelings and confessions, or matters over which there is generally conflict. On the other, the acceptance of a theme is a presupposition for making negative comments on contributions; for rejecting, correcting, or modifying their content. The thresholds of thematization can be very high because by accepting a theme one may have to deal with too many negative contributions. [...]

Themes have a factual content, which enables them to coordinate contributions: one may talk about an actress's love affairs, the market rate and why it is so, a new book, or the children of foreign workers. Specialization sets no boundaries here—except perhaps those that arise from an interest in continuing communication. Themes also have a temporal aspect, however. One can recall earlier contributions to a theme. Themes are old or new, already boring or still interesting, and all of this may be different for different participants. Finally themes reach a saturation point, after which new contributions are no longer anticipated. If it is to remain alive, an old theme must then recruit new participants. By contrast, a new theme may for many participants be too new to stimulate generally meaningful contributions.

The social aspect of thematic choice is important, too, as the example of "amicability" indicated. This implies more than congeniality, more than that themes more or less adapt themselves to participants and their possible contributions. The social dimension is actualized above all when communication as visible behavior binds the participants to a greater or lesser degree. This means that with their communication they say something about themselves, their opinions, attitudes, experiences, wishes, discernment, and interests. Thus communication also serves self-presentation and self-knowledge. In effect, it can force one into a form and finally make one be what one appeared to be in communication: the seducer must eventually fall in love.

This binding effect appears very clearly when communicative themes adopt moral overtones or are entirely moral themes. Morality regulates the conditions of reciprocal esteem or contempt. One can incite esteem with themes suitable for moralizing communication. One can present oneself as worthy of esteem and make it difficult for others to contradict him. One can test whether someone deserves esteem. Or one can try to trap others in the net of the conditions for esteem in order to carry them off in it. And one can trick others to moral self-commitments, then leave them in the lurch. One can also use moralization to show that one puts little importance on the esteem of a specific partner. Depending on how much freedom society makes possible in dealing with morality, morality can serve to increase solidarity in the way Durkheim proposed or to accentuate critique, distancing, and conflict.

Thus themes serve as factual/temporal/social structures within the communication process, and they function as generalizations insofar as they do not restrict which contributions can be made at what time, in which sequence, and by whom. Meaning references can be actualized on the thematic level that in a single communicative event could hardly be detected. Communication, therefore, is typically, although not necessarily, a process steered by themes. At the same time, themes reduce the complexity opened up by language. Mere linguistic correctness of formulation does not say enough. Only by themes can one control the correctness of one's own and others' communicative behavior as appropriate or not for the theme. To this extent themes are, as it were, the action programs of language. When the immediate theme is the best way of catching mice in a mousetrap, one can make a great many contributions, but can no longer say just anything. The theme gives sufficient orientation for one to choose one's contributions quickly and check the appropriateness of others' contributions. One can test the moral sensibility of the participants by mentioning the torments suffered by the mice and change the theme if one detects that the theme is exhausted for oneself and the other participants. (Social Systems 1995: 155 - 157.