If you are in the outside world, thought Abbess Catherine, a misdemeanour or fault can go almost unnoticed; conscience is not as tender, as cleansed and polished with many rubbings as with us-- examinations of conscience every day, every week a Chapter of Faults, and instant acknowledgments. Yes, thought Abbess Catherine, it is the difference between a rough and pitted surface and one so planed down and polished that the least mark shows.
I love that image of the surface planed and polished so that the least mark shows. It strikes me that the novel is that polished surface. The contrast between the events in the outside world, Phillipa's past and Penny present especially (trying to avoid spoilers for those who haven't yet got to those sections-- or should I not worry about that?), and the dramas of life inside the enclosure. I'm especially thinking of the drama between Cecily and Dame Maura which results in Dame Maura's departure for Canada. In the outside world the emotional play between the two nuns would be almost not worth mentioning. And yet the consequences of that tension are just as far reaching as the much more obvious conflict of the loss of a child.