COGNITIVE FEATURES OF THE TOPIC
A number of cognitive features have been associated with major topic entities. First, the topic entity is inherent to the event described and it initiates the action.
Second, the topic entity is typically high on what is called the empathy hierarchy. This has to do with what attracts our empathy. It starts from the speaker, since we all empathize most with ourselves, and continues as follows:
Speaker > hearer > human > animal > physical object > abstract entity
After the speaker, the hearer – as co-participant in a conversation – can be important, and is included with the speaker in the inclusive use of ‘we’, as in 1. But in many discourses a 3rd person topic is even more common, in that we frequently talk and write about people, creatures and things distinct from the speaker and hearer. Abstract entities come last in the empathy hierarchy.
A third feature is definiteness. This is a subjective factor since it depends on whether speakers and hearers have established empathy with the topic. When contact has been established, the topic is easily accessible and is definite.
Fourth, the topic is the most salient participant on the scene of discourse.
From the point of view of cognitive salience, all these features are closely associated with the Subject function in English. The prototypical Subject referent is inherent to the event described in the clause; it fulfils the semantic function of Agent, if there is an Agent, and initiates the action. It is typically human and definite and is the main participant at any one point on the scene of discourse as represented in a particular clause or utterance. Subject and Topic are therefore closely related in English. (It must be pointed out that this does not imply that all Subjects have these characteristics.)
These features are not, however, necessarily associated with Theme. Theme and Topic are quite different types of category. Topics are what a text, section or clause is about, and Topic is always conceptualized as an entity or a nominalization. Theme, on the other hand, is what the speaker or writer chooses as the point of departure for the message in any one clause or sentence. It may be an entity, a circumstance or an attribute. Only entities initiate referential chains. Let’s look now at the main types of themes, starting from the most central.
