Northrop Frye, commenting on Blake's consistency in strongly held views, notes Blake "himself says that his notes on [Joshua] Reynolds, written at fifty, are 'exactly Similar' to those on Locke and Bacon, written when he was 'very Young'. Even phrases and lines of verse will reappear as much as forty years later. Consistency in maintaining what he believed to be true was itself one of his leading principles ... Consistency, then, foolish or otherwise, is one of Blake's chief preoccupations, just as 'self-contradiction' is always one of his most contemptuous comments".
Blake abhorred slavery and believed in racial and sexual equality. Several of his poems and paintings express a notion of universal humanity: "As all men are alike (tho' infinitely various)". In one poem, narrated by a black child, white and black bodies alike are described as shaded groves or clouds, which exist only until one learns "to bear the beams of love":
When I from black and he from white cloud free, And round the tent of God like lambs we joy: Ill shade him from the heat till he can bear, To lean in joy upon our fathers knee. And then I'll stand and stroke his silver hair, And be like him and he will then love me. (23-8, E9)
Blake retained an active interest in social and political events throughout his life, and social and political statements are often present in his mystical symbolism. His views on what he saw as oppression and restriction of rightful freedom extended to the Church. His spiritual beliefs are evident in Songs of Experience (1794), in which he distinguishes between the Old Testament God, whose restrictions he rejected, and the New Testament God whom he saw as a positive influence.
From a young age, William Blake claimed to have seen visions. The first may have occurred as early as the age of four when, according to one anecdote, the young artist "saw God" when God "put his head to the window", causing Blake to break into screaming. At the age of eight or ten in Peckham Rye, London, Blake claimed to have seen "a tree filled with angels, bright angelic wings bespangling every bough like stars." According to Blake's Victorian biographer Gilchrist, he returned home and reported the vision and only escaped being thrashed by his father for telling a lie through the intervention of his mother. Though all evidence suggests that his parents were largely supportive, his mother seems to have been especially so, and several of Blake's early drawings and poems decorated the walls of her chamber. On another occasion, Blake watched haymakers at work, and thought he saw angelic figures walking among them.
Blake claimed to experience visions throughout his life. They were often associated with beautiful religious themes and imagery, and may have inspired him further with spiritual works and pursuits. Certainly, religious concepts and imagery figure centrally in Blake's works. God and Christianity constituted the intellectual centre of his writings, from which he drew inspiration. Blake believed he was personally instructed and encouraged by Archangels to create his artistic works, which he claimed were actively read and enjoyed by the same Archangels. In a letter of condolence to William Hayley, dated 6 May 1800, four days after the death of Hayley's son, Blake wrote:
I know that our deceased friends are more really with us than when they were apparent to our mortal part. Thirteen years ago I lost a brother, and with his spirit I converse daily and hourly in the spirit, and see him in my remembrance, in the region of my imagination. I hear his advice, and even now write from his dictate.
In a letter to John Flaxman, dated 21 September 1800, Blake wrote:
[The town of] Felpham is a sweet place for Study, because it is more spiritual than London. Heaven opens here on all sides her golden Gates; her windows are not obstructed by vapours; voices of Celestial inhabitants are more distinctly heard, & their forms more distinctly seen; & my Cottage is also a Shadow of their houses. My Wife & Sister are both well, courting Neptune for an embrace... I am more famed in Heaven for my works than I could well conceive. In my Brain are studies & Chambers filled with books & pictures of old, which I wrote & painted in ages of Eternity before my mortal life; & those works are the delight & Study of Archangels. (E710)
In a letter to Thomas Butts, dated 25 April 1803, Blake wrote:
Now I may say to you, what perhaps I should not dare to say to anyone else: That I can alone carry on my visionary studies in London unannoy'd, & that I may converse with my friends in Eternity, See Visions, Dream Dreams & prophecy & speak Parables unobserv'd & at liberty from the Doubts of other Mortals; perhaps Doubts proceeding from Kindness, but Doubts are always pernicious, Especially when we Doubt our Friends.
In A Vision of the Last Judgement Blake wrote:
Error is Created Truth is Eternal Error or Creation will be Burned Up & then & not till then Truth or Eternity will appear It is Burnt up the Moment Men cease to behold it I assert for My self that I do not behold the Outward Creation & that to me it is hindrance & not Action it is as the Dirt upon my feet No part of Me. What it will be Questiond When the Sun rises do you not see a round Disk of fire somewhat like a Guinea O no no I see an Innumerable company of the Heavenly host crying Holy Holy Holy is the Lord God Almighty I question not my Corporeal or Vegetative Eye any more than I would Question a Window concerning a Sight I look thro it & not with it. (E565-6)
Aware of Blake's visions, William Wordsworth commented, "There was no doubt that this poor man was mad, but there is something in the madness of this man which interests me more than the sanity of Lord Byron and Walter Scott." In a more deferential vein, writing in A Short Biographical Dictionary of English Literature, John William Cousins wrote that Blake was "a truly pious and loving soul, neglected and misunderstood by the world, but appreciated by an elect few", who "led a cheerful and contented life of poverty illumined by visions and celestial inspirations.". Blake's sanity was called into question as recently as the publication of the 1911 Encyclopædia Britannica, whose entry on Blake comments that "The question whether Blake was or was not mad seems likely to remain in dispute, but there can be no doubt whatever that he was at different periods of his life under the influence of illusions for which there are no outward facts to account, and that much of what he wrote is so far wanting in the quality of sanity as to be without a logical coherence.".