Few fantasies are harder to wipe away than the romance of a clean slate. Every January, when we’re twitchy with regret and self-loathing, advertisers blare, “New Year, new you,” urging us to jettison our failures and start fresh. In fiction, self-reinvention is a perennial theme, often shadowed by the suspicion that it can’t be done. Lately, novelists have put a political spin on the idea, counterposing hopeful acts of individual self-fashioning to the immovable weight of circumstance. Halle Butler’s “The New Me” (2019), a millennial office satire, finds its temp heroine, Millie, trying to life-hack her way out of loneliness and professional drift—buy a plant, whiten her teeth, make friends, think positive. The trouble, Butler suggests, is that Millie can’t begin anew until the world does. It’s a vision steeped…