The economic problem of womanhood
I became increasingly conscious of the fact that Lily's hamartia - "money!", a fact which she acknowledges to both herself and Selden - echoes a deeper and more problematic tragedy for our protagonist. When she realises that her lifestyle is financially unsustainable, she too realises that not only is her entire beingeconomically unsustainable, the economy itself refuses to sustain her. As she once said very succintly in Book 2, Chapter 12:
I have tried hard - but life is difficult, and I am a very useless person. I can hardly be said to have an independent existence. I was just a screw or a cog in the great machine I called life, and when I dropped out of it I found I was of no use anywhere else. What can one do when one finds that one only fits into one hole? One must get back to it or be thrown out into the rubbish heap - and you don't know what it's like in the rubbish heap!
It is telling that as Lily sums up her fate and position in life she continually defers to the word "one" in a constant reminder that she has been raised in a way that has only allowed her a single position in life, the further implication being that the economy (or society - one finds both domains to be the one and the same in the material, affluent world of House of Mirth) itself only has one position for Lily: to be a man's wife. Having been raised as such ("Since she had been brought up to be ornamental, she could hardly blame herself for failing to serve any practical purpose"), it is no wonder that she both scoffs at the wage-earning woman and fails at her subsequent efforts to be one; but her great tragedy is seen when she chooses to continually reject offers of marriage in her aspiration for greater, "nobler" values (might one dare say it? i.e. love, or in some cases, the possibility of greater wealth in another man).
The novel thus establishes a conflict between two versions of womanhood, with being a wage-earner at one end and being blissfully married at the other - but this is also conflated with being a working classwage-earner versus an upper classmarried woman. This conflict of difference gets dashed away when Lily is confronted by the image of Nettie Struther, whose kitchen is at once shabby and yet warm and comforting in her marital, conjugal bliss.
And then this sets up a second conflict of womanhood - that between being independent/single and being dependent on a man. Lily is constantly tempted by the latter and reverts, in what seems like a show of strength, to the former. But again our confidence in Lily wavers when that final image of her cradling a baby comforts her to sleep at the end of the book. What does that mean for the empowered, independent female? Must a woman be eternally resigned to her single fate as a child-bearer? Can she be anything more?