In her later years Julia was usually identified in print as ‘Miss Julia Wedgwood, the author of The Moral Ideal’. Published in 1888 after 20 years of work and reflection, The Moral Ideal: A Historic Study was the most characteristic of her books and the one she herself saw as her magnum opus. She thought it important enough to rework it for a younger generation with the help of E. M. Forster, publishing a revised and extended version in 1907. It contained the essence of her thinking about what she saw as man's instinctive search for spiritual meaning and closer union, one with another and with the divine.

The Moral Ideal was a remarkably ambitious book. The extent of learning it displayed, particularly in its footnotes, gave her a claim to be the best-read woman in England after the death of George Eliot. She considered not just Homer, Sophocles, Plato, Virgil, Lucretius and Marcus Aurelius but also the Rig Veda and the Upanishads, Zoroaster, the Gnostics, Epictetus and Philo, St Augustine and Julian the Pelagian. Except when she referred to foreign commentaries, she rarely dealt with secondary works, going instead to the primary sources and quoting from Greek, Latin, German, French and Italian. Sometimes, as with the Rig Veda or the Alexandrian philosopher Philo, she preferred older translations in German to the more accessible English texts. Nor did she hold back from disagreeing about Plato with the pre-eminent authority Benjamin Jowett. At a time when ‘the amateur scholarship that had been the byword of the mid-century’ had been replaced by increased academic specialization in the study of the classics, Julia boldly entered this newly reserved territory. For a woman, her book was an extraordinary achievement. Some of the reviewers hardly knew what to make of it: others were lavish in their praise, none more so than Hutton. An eclectic mix of intellectual influences was detectible in it: Kant and Hegel, Carlyle, Erskine, Maurice and Cobbe, Matthew Arnold, Jowett and Walter Pater as well as more esoteric writers like Mary Everest Boole and Balfour Stewart. One influence was never overtly mentioned but frequently discernible: Browning.