Themes
Principles over costume
Wilde keeps separating a dress from the principle behind it. There is 'absolutely no limit' to the attractive costumes that can be revived or invented, but unless one is 'founded on principles and exemplified laws' it is useless to reform. So he offers the Newcastle drawing 'not a revival of a dead costume, but a realisation of living laws', and compares it to a square lintel or a pointed arch, good not for being Greek or Gothic but for doing its work in the best way.
Beauty is organic
The piece's widest claim is that beauty 'comes, not from without, but from within, not from any added prettiness, but from the perfection of its own being.' Ugliness is 'want of fitness', 'failure', 'uselessness, such as ornament in the wrong place'; beauty, quoting 'some one', is 'the purgation of all superfluities'. Wilde turns this on Huyshe's 'practical views': since ugliness is always extravagant and wasteful, it is 'always the sign that somebody has been unpractical.'
Experience against theory
Wilde's authority is his own body. Huyshe admits he has never been 'guilty of the eccentricity' of wearing the dress he recommends; Wilde has worn it 'many times, both in public and in private', and speaks from 'absolute experience' of its tight knee-breeches. The same appeal to practice runs through the replies to the 'Old Sailor', drawn from Oxford runners and rowers, and on clogs, from a lady who remembered those of her girlhood with affection.
Dress for both sexes
Wilde treats men's and women's dress as governed by the same laws. He proposes clogs, the divided skirt or loose knickerbockers for women, and dismisses Huyshe's threat not to propose to girls who wear them: 'every right article of apparel belongs equally to both sexes.' His one condition is that a garment show what it is: the divided skirt must stop pretending to be an ordinary skirt, since 'the moment it imitates a dress it is lost'.