There is either leading or being led. Changing or being changed. Action or passion. And of course the manner of leading or being led – ductus, from ducere (to lead).
In palaeography– the study of ancient writing –, ductus is described as ‘the overall, general “nature” of the production of a given script, defined in terms of the “number, sequence, and direction of the strokes used in forming each letter of the script’s alphabet’.
In art history, ductus is also sometimes referred to as the manner of structuring a ‘readable’ space, most often a sacred space, where symbolism, metaphor and embodied space converge to create a space of interpretation. Medieval churches were structured in such a way so that the hermeneutic ductus would be easy for the visitor, meaning that anyone entering the church and the following a pre-established track would be confronted with a narrative inscribed in the architectural space itself (nave, transept, column capitals, paintings, objects, etc).
The story you want to tell will qualify your ductus. The way you write will shape the ductus you follow. To communicate is to structure the space in between and to create the channel in which your ductus will pass through.