This thesis examines the nature of the relationship between documentary and social practices. In particular it seeks to develop and theorise a mode of documentary practice in which social practices in general are dialogised rather than represented. I characterise social practices as consisting of a largely tacit consensus in ways of acting and understanding. This consensus is, I argue however, inherently open to re-evaluation and re-articulation in practice itself; and it is as part of rather than as a representation of-such processes that dialogical documentary operates. In the written thesis, which discusses a number of specific documentaries in relation to their overall approach to practices, I argue for a mode of documentary based not in representational strategies of external observation and objective overview, but rather in the dialogising of moments of practice. An act that has been dialogised is revealed as involving a degree of ambiguity or heterogeneity-and hence the possibility of a re-evaluation, i. e., re-negotiation of practices themselves. For dialogical documentary objective representation is neither means nor goal; on the contrary tendential intervention becomes a legitimate and central method-both in the local situation, where the filmmaking process provokes behaviour and reflection rather than merely recording it; and on the level of public discourse, to which the documentary raises particular instances of practice by enunciating them, or allowing them to be enunciated, within a discursive field. These concerns are directly reflected in the main practice element of the thesis-a documentary project exploring the rehearsal of a piece of music by Christian Wolff called Changing the System (1973). This exploration is based around the score of the piece, which, offering different possibilities for its realisation, both on the macro and micro level, requires explicit dialogical interaction between the players. | 
