He advises them to cultivate a fondness for dress, because a fondness for dress, he asserts, is natural to them. (2.37)
Jean-Jacques Rousseau advises young ladies to dress up and look pretty because a love for dressing up and looking pretty is natural for them. But here's the weird thing: why would they have to be encouraged if this behavior is so natural to them? You don't have to, for example, encourage a person to drink water when they're thirsty.
It is time to effect a revolution in female manners. (3.25)
Wollstonecraft thinks that that only way for women to move forward is to demand better access to education, and make men rethink the importance of manners. The focus can no longer be on appearance and nicety. People need to care about higher things like philosophy and morality.
I do earnestly wish to see the distinction of sex confounded in society. (4.18)
Many people in Wollstonecraft's time would have thought she was crazy for saying that she'd like to see the lines between men and women blurred. But the truth is that she's sick and tired of the distinction between a "masculine" focus on intelligence and a "feminine" focus on appearances.
Civilized women are, therefore, so weakened by false refinement, that, respecting morals, their condition is much below what it would be were they left in a state nearer to nature. (4.26)
Women might actually be more moral if they were totally left alone by society and not educated at all. Traditional female education, though, focuses so much on appearances and superficial things that in Wollstonecraft's mind, it actually makes women worse as people.
I am fully persuaded that we should hear of none of these infantine airs, if girls were allowed to take sufficient exercise, and not confined in close rooms till their muscles are relaxed, and their powers of digestion destroyed. (4.34)
Wollstonecraft insists that one of the main reasons women's minds are corrupted is because their bodies are never given a chance to develop properly. From a young age, ladies are kept away from physical sports and taught not to exercise their muscles. Wollstonecraft insists that this lack of exercise and nutrition ends up giving women weak minds.
But, I will venture to assert that their reason will never acquire sufficient strength to enable it to regulate their conduct, whilst the making an appearance in the world is the first wish of the majority of mankind. (4.77)
Women will never learn how to properly use their minds if the world won't stop valuing their appearance over everything else. You can still see this kind of tension today in the way that advertisements and fashion spreads still have an insane control over women's self-image.
Girls are from the earliest infancy fond of dress. Not content with being pretty, they are desirous of being thought so; we see, by all their little airs, that this thought engages their attention. (5.11)
Young women are fond of dress, but not just because they want to be pretty. The most important thing in the world is for people to think they're pretty. Women are taught to seek out affirmation of their beauty, instead of being content with simply being beautiful.
It is this system of dissimulation, throughout the volume, that I despise. Women are always to seem to be this and that. (5.96)
One thing that Wollstonecraft hates is the way women are taught to value seeming above being. If the way people see you is seen as the ultimate accomplishment, you'll never spend any time thinking about who you are on the inside.
How much more respectable is the woman who earns her own bread by fulfilling any duty, than the most accomplished beauty! (9.30)
Wollstonecraft states repeatedly that beauty is transient, but a solid skill set is permanent. Furthermore, the "accomplishment" of beauty can never be internalized and can only be understood through outside affirmation. If you're really good at, say, carpentry, you can say to yourself "Dang, I built a really nice cabinet." You can't get the same sense of accomplishment by being a pretty face.
Ignorance and the mistaken cunning that nature sharpens in weak heads as a principle of self-preservation, render women very fond of dress. (13.42)
Wollstonecraft thinks that women's obsession with dresses and outward beauty are symptoms of the way society warps their minds. She doesn't believe that women are naturally superficial or shallow. It's society's fault for giving them nothing to think about other than looking pretty.