difficulty in the translation of The Importance of Being Earnest

[xiaoxiaomuyu]

dear all, i have trouble with my translation of the underlined and need your help.
this is a passage from Oscar Wilde's The Importance of Being Earnest. Actually it is this lady's opinion of modern education and about how it would affect the upper classes. I think some kind of irony is intended here, but i don't know how to represent it in my translation. i am especially puzzled by "unsound". what did the lady mean by unsound?



LADY BRACKNELL. I am pleased to hear it. I do not approve of anything that tampers with natural ignorance. Ignorance is like a delicate exotic fruit; touch it and the bloom is gone. The whole theory of modern education is radically unsound. Fortunately in England, at any rate, education produces no effect whatsoever. If it did, it would prove a serious danger to the upper classes, and probably lead to acts of violence in Grosvenor Square.

[SoothingDave]

Unsound | Define Unsound at Dictionary.com

It is tricky to guess exactly what sense the author may have meant, especially since wordsmiths at times play on the multiple meanings of words.

Since he approves of leaving ignorance in its natural state, I would argue that he likely meant mostly sense 4 ("not well-founded or valid") but he likely meant some of sense 1 as well ("unhealthy, diseased, or disordered").

[konungursvia]

Faulty, incorrect, flawed, broken.