Technical aiding the story - the push for new technology. Cause + reasoning. Think Portrait
Almost every Kubrick film is a showcase for some major innovation in technique – in 2001 it was the revolutionary visual effects; in The Shining, his mastery of the Steadicam. On Barry Lyndon, Kubrick and cinematographer John Alcott set themselves the task of shooting as many sequences as possible without recourse to electrical light.
The stately, painterly, often determinedly static quality of Barry Lyndon was at least in part dictated by this stylistic choice – lit only by candles, the actors in the many sequences of dining and gambling were under instruction to move as slowly as possible, to avoid underexposure. But it fits perfectly with Kubrick's gilded-cage aesthetic – the film is consciously a museum piece, its characters pinned to the frame like butterflies.
Kubrick and Alcott looked to the landscapes of Watteau and Gainsborough; the day-lit interiors owe a lot to Hogarth, with whom Thackeray had always been fascinated.
Subjected to the director's infamous regime of many, many arduous takes, their faces light up the film and the era, like a series of fine, carefully hung, oil portraits. Kubrick's cast may have been required to sit for these for days and weeks on end, but no one could say the results weren't worth it.
https://www.telegraph.co.uk/films/2016/07/27/kubrick-by-candlelight-how-barry-lyndon-became-a-gorgeous-period/
Everything in life pre planned - Idea of fate.