6. The Theme
6. The ThemeThe textual metafunction covers language used as an instrument of communication with which we build up cohesive and coherent sequences. Each clause carries a message, and so the textual aspect can be seen as fulfilling a message function of clauses and is therefore very closely connected to their information structure. In Hallidayan grammar there is an interrelationship between two systems of analysis which both affect the structure of the clause: Information structure and Thematic structure. The former system involves constituents that are labelled Given and New, and the latter system involves constituents that are labelled Theme and Rheme. The two systems are in some ways rather similar in structure and in many clauses the Theme is equivalent to Given information (cf. Prince (1981)), and the Rheme is considered equivalent to New information. Following Halliday (1994, p.299), who treats Given/New and Theme/Rheme as separate approaches, the focus of the current study is on the system of Theme and Rheme.
A common interpretation of Theme is to say that it is "the idea represented by the constituent at the starting point of the clause" (Bloor & Bloor (1995, p.72)). According to Halliday (1994, p.37) the Theme is viewed to be "the point of departure of the message" where each clause is said to carry a message. Another way of expressing the Theme is to say that it is what the clause is about. This explanation however might be misleading since in some cases it might be difficult to distinguish Theme from subject. Therefore the explanation of the Theme as being the starting point of the clause or for the message, is to be preferred (Thompson (1996, p.119)).
The identification of the Theme is then based on word order. The element which comes first in the clause is the Theme and what comes after it is the Rheme. According to Halliday the Theme analysis involves two layers of analysis: the Theme/Rheme analysis, and within the Theme the level of topical, textual, or interpersonal analysis (a multiple Theme analysis). Clauses which have only one Thematic constituent are said to have simple Themes, and clauses which have more than one constituent are said to have a multiple Thematic structure (Bloor & Bloor (1995, p.77)). Each clause in a text has a Theme which relates to the ideational function of language and is labelled the topical Theme of the clause. In clauses which have simple Themes, with only one Theme identified, the Theme is the topical Theme. However, some clauses can also be assigned a textual and an interpersonal Theme. The textual Theme almost always is the first part of the Theme and fulfils a linking function. It is therefore usually realized by structural conjunctions, relatives, conjunctives, or continuatives. The interpersonal Theme usually follows the textual Theme and typically includes one or more of the following elements: a Finite (an auxiliary verb), a Wh-element, a Vocative, or an Adjunct (typically an adverb). The interpersonal Theme mainly conveys the writer's attitude towards, comment on or assessment of the message of the clause. The ideational or topical Theme is the element of the clause that expresses some kind of representational meaning. Technically, it is a function from the transitivity structure of the clause which implies that it can be either a participant, a circumstance (i.e. giving information about time, place, manner, cause etc.), or a process. In this study, following Halliday (1994, p.53), the Theme comprises all elements up to and including the topical Theme which is then also the boundary between the Theme and the Rheme, as in the following example:
Example 1:
It is important to remember that every clause must contain one and only one topical Theme. Once the topical Theme has been identified, all the clause constituents to the right can be consigned to the Rheme role.
A focus on the Theme element reveals which linguistic elements the Ph.D. students place as starting points of their clauses. Their conscious or unconscious choices of Themes reflect the message of their clauses and hence the intended communicative purpose of their homepage texts. Furthermore, analysing the choices of topical Themes causes the homepage authors' strategy with the texts to crystallize even further, since the patterns of the topical choices in a text provide a possible interpretation of the Mode8 of a text. That is an analysis of the topical Themes gives an indication of the roles they are playing in the homepage interaction between the writer and the reader of the texts. In an academic or scholarly text, for example, "the Mode demands the Thematization of abstractions: we do not depart from our own experience, but from our considered generalizations about people, situations, causes" (Eggins (1994, p.302)). Whereas in a face-to-face conversation we depart from our own experiences. Our point of departure is ourselves. The Modes of a scholarly text and a face-to-face conversation are different and consequently the choices of topical Themes.
