p 284-285
Now, of course these secrets had their purpose, though what this purpose might be, it was up to the children of the day to try to guess. The children have to feel their way to table manners, and where one may play and where one may not play and, most especially, what games one may not play; then they have to sense why the servants and the corridors and the toilets and the bathrooms are invisible and why naked walls are a threat; and why one never talks about money and never swears. Thus —by leaving the children to guess, instead of just telling them, straight out— creates a tension and ensures that one's children will grow up imbued with a vibrant vigilance. This schooling in vigilance should guarantee that the young people may well relax, but never to the extend that they become lax and forget themselves and grow inconsistent. Part of the truth behind this reticence is that it creates an abiding state of tension.