I contradict myself
"God, we'll simply have to dress the character. I want puce gloves and green boots. Do I contradict myself? Very well then, I contradict myself." Mulligan's perpetual spray of quotations from his favorite writers (Swinburne, Russell, Homer, Xenophon, Nietzsche, Yeats, Wilde) continues as he rummages through his clothing trunk. Apparently, he is applying Walt Whitman's famous saying to the fact that he chooses to accessorize his yellow waistcoat with green boots and dark red gloves.
In Song of Myself, Whitman wrote:
Do I contradict myself?
Very well then I contradict myself,
(I am large, I contain multitudes.)
Gifford notes the relevant fact that Whitman’s reputation was high in England at the end of the nineteenth century, citing “Swinburne’s praise of him as the poet of the ‘earth-god freedom’ in To Walt Whitman in America (1871).”
Mulligan's determination to dress in the outrageous fashion of the fin de siècle avant-garde ("we'll simply have to dress the character") coheres, then, with the quotation that accessorizes the accessories.
Stephen thinks of these lines in Proteus, and in Scylla and Charybdis he too mentions Whitman in the course of his Shakespeare talk.