First Part Chapter 18

You speak of vice; and it is possible that, after all, reason and
reflection produce a result not dissimilar from what we call by that
name. For what does a woman mean by it but perversion of feeling
through calculation? Passion is vicious when it reasons, admirable
only when it springs from the heart and spends itself in sublime
impulses that set at naught all selfish considerations. Sooner or
later, dear one, you too will say, "Yes! dissimulation is the
necessary armor of a woman, if by dissimulation be meant courage to
bear in silence, prudence to foresee the future."

Every married woman learns to her cost the existence of certain social
laws, which, in many respects, conflict with the laws of nature.
Marrying at our age, it would be possible to have a dozen children.
What is this but another name for a dozen crimes, a dozen misfortunes?
It would be handing over to poverty and despair twelve innocent
darlings; whereas two children would mean the happiness of both, a
double blessing, two lives capable of developing in harmony with the
customs and laws of our time. The natural law and the code are in
hostility, and we are the battle ground. Would you give the name of
vice to the prudence of the wife who guards her family from
destruction through its own acts? One calculation or a thousand, what
matter, if the decision no longer rests with the heart?