It is helpful to distinguish between two usages of deixis, gestural and symbolic, as well as non-deictic usages of frequently deictic words. Gestural deixis refers, broadly, to deictic expressions whose understanding requires some sort of audio-visual information. A simple example is when an object is pointed at and referred to as “this” or “that”. However, the category can include other types of information than pointing, such as direction of gaze, tone of voice, and so on. Symbolic usage, by contrast, requires generally only basic spatio-temporal knowledge of the utterance. So, for example
- I broke this finger.
requires being able to see which finger is being held up, whereas
- I love this city.
requires only knowledge of the current location. In a similar vein,
- I went to this city one time …
is a non-deictic usage of "this", which does not reference anything specific. Rather, it is used as an indefinite article, much the way "a" could be used in its place.