19th-century "free love" movement
Since his death, William Blake has been claimed by those of various movements who apply his complex and often elusive use of symbolism and allegory to the issues that concern them. In particular, Blake is sometimes considered (along with Mary Wollstonecraft and her husband William Godwin) a forerunner of the 19th-century "free love" movement, a broad reform tradition starting in the 1820s that held that marriage is slavery, and advocated the removal of all state restrictions on sexual activity such as homosexuality, prostitution, and adultery, culminating in the birth control movement of the early 20th century. Blake scholarship was more focused on this theme in the earlier 20th century than today, although it is still mentioned notably by the Blake scholar Magnus Ankarsjö who moderately challenges this interpretation. The 19th-century "free love" movement was not particularly focused on the idea of multiple partners, but did agree with Wollstonecraft that state-sanctioned marriage was "legal prostitution" and monopolistic in character. It has somewhat more in common with early feminist movements (particularly with regard to the writings of Mary Wollstonecraft, whom Blake admired).
Blake was critical of the marriage laws of his day, and generally railed against traditional Christian notions of chastity as a virtue. At a time of tremendous strain in his marriage, in part due to Catherine's apparent inability to bear children, he directly advocated bringing a second wife into the house. His poetry suggests that external demands for marital fidelity reduce love to mere duty rather than authentic affection, and decries jealousy and egotism as a motive for marriage laws. Poems such as "Why should I be bound to thee, O my lovely Myrtle-tree?" and "Earth's Answer" seem to advocate multiple sexual partners. In his poem "London" he speaks of "the Marriage-Hearse" plagued by "the youthful Harlot's curse", the result alternately of false Prudence and/or Harlotry. Visions of the Daughters of Albion is widely (though not universally) read as a tribute to free love since the relationship between Bromion and Oothoon is held together only by laws and not by love. For Blake, law and love are opposed, and he castigates the "frozen marriage-bed". In Visions, Blake writes:
Till she who burns with youth, and knows no fixed lot, is bound In spells of law to one she loathes? and must she drag the chain Of life in weary lust? (5.21-3, E49)
In the 19th century, poet and free love advocate Algernon Charles Swinburne wrote a book on Blake drawing attention to the above motifs in which Blake praises "sacred natural love" that is not bound by another's possessive jealousy, the latter characterised by Blake as a "creeping skeleton". Swinburne notes how Blake's Marriage of Heaven and Hell condemns the hypocrisy of the "pale religious letchery" of advocates of traditional norms. Another 19th-century free love advocate, Edward Carpenter (1844–1929), was influenced by Blake's mystical emphasis on energy free from external restrictions.
In the early 20th century, Pierre Berger described how Blake's views echo Mary Wollstonecraft's celebration of joyful authentic love rather than love born of duty, the former being the true measure of purity. Irene Langridge notes that "in Blake's mysterious and unorthodox creed the doctrine of free love was something Blake wanted for the edification of 'the soul'." Michael Davis's 1977 book William Blake a New Kind of Man suggests that Blake thought jealousy separates man from the divine unity, condemning him to a frozen death.
As a theological writer, Blake has a sense of human "fallenness". S. Foster Damon noted that for Blake the major impediments to a free love society were corrupt human nature, not merely the intolerance of society and the jealousy of men, but the inauthentic hypocritical nature of human communication. Thomas Wright's 1928 book Life of William Blake (entirely devoted to Blake's doctrine of free love) notes that Blake thinks marriage should in practice afford the joy of love, but notes that in reality it often does not, as a couple's knowledge of being chained often diminishes their joy. Pierre Berger also analyses Blake's early mythological poems such as Ahania as declaring marriage laws to be a consequence of the fallenness of humanity, as these are born from pride and jealousy.
Some scholars have noted that Blake's views on "free love" are both qualified and may have undergone shifts and modifications in his late years. Some poems from this period warn of dangers of predatory sexuality such as The Sick Rose. Magnus Ankarsjö notes that while the hero of Visions of the Daughters of Albion is a strong advocate of free love, by the end of the poem she has become more circumspect as her awareness of the dark side of sexuality has grown, crying "Can this be love which drinks another as a sponge drinks water?" Ankarsjö also notes that a major inspiration to Blake, Mary Wollstonecraft, similarly developed more circumspect views of sexual freedom late in life. In light of Blake's aforementioned sense of human 'fallenness' Ankarsjö thinks Blake does not fully approve of sensual indulgence merely in defiance of law as exemplified by the female character of Leutha, since in the fallen world of experience all love is enchained. Ankarsjö records Blake as having supported a commune with some sharing of partners, though David Worrall read The Book of Thel as a rejection of the proposal to take concubines espoused by some members of the Swedenborgian church.
Blake's later writings show a renewed interest in Christianity, and although he radically reinterprets Christian morality in a way that embraces sensual pleasure, there is little of the emphasis on sexual libertarianism found in several of his early poems, and there is advocacy of "self-denial", though such abnegation must be inspired by love rather than through authoritarian compulsion. Berger (more so than Swinburne) is especially sensitive to a shift in sensibility between the early Blake and the later Blake. Berger believes the young Blake placed too much emphasis on following impulses, and that the older Blake had a better formed ideal of a true love that sacrifices self. Some celebration of mystical sensuality remains in the late poems (most notably in Blake's denial of the virginity of Jesus's mother). However, the late poems also place a greater emphasis on forgiveness, redemption, and emotional authenticity as a foundation for relationships.