The summer when nineteen-year-old Emily Dickinson met the love of her life — the orphaned mathematician-in-training Susan Gilbert, who would come to be the poet’s greatest muse, her mentor, her primary reader and editor, her fiercest lifelong attachment, her “Only Woman in the World” — another intense, label-defying love was igniting in the heart of another literary titan-to-be some fifty miles westward. That other love unfolds alongside Dickinson’s in Figuring — a book I wrote to explore, among other existential…