Blake had a complex relationship with Enlightenment philosophy. His championing of the imagination as the most important element of human existence ran contrary to Enlightenment ideals of rationalism and empiricism.[96] Due to his visionary religious beliefs, he opposed the Newtonian view of the universe. This mindset is reflected in an excerpt from Blake's Jerusalem:
Blake's Newton (1795) demonstrates his opposition to the "single-vision" of scientific materialism: Newton fixes his eye on a compass (recalling Proverbs 8:27,[97] an important passage for Milton)[98] to write upon a scroll that seems to project from his own head.[99]I turn my eyes to the Schools & Universities of Europe And there behold the Loom of Locke whose Woof rages dire Washd by the Water-wheels of Newton. black the cloth In heavy wreathes folds over every Nation; cruel Works Of many Wheels I view, wheel without wheel, with cogs tyrannic Moving by compulsion each other: not as those in Eden: which Wheel within Wheel in freedom revolve in harmony & peace. (15.14–20, E159)
Blake believed the paintings of Sir Joshua Reynolds, which depict the naturalistic fall of light upon objects, were products entirely of the "vegetative eye", and he saw Locke and Newton as "the true progenitors of Sir Joshua Reynolds' aesthetic".[100] The popular taste in the England of that time for such paintings was satisfied with mezzotints, prints produced by a process that created an image from thousands of tiny dots upon the page. Blake saw an analogy between this and Newton's particle theory of light.[101] Accordingly, Blake never used the technique, opting rather to develop a method of engraving purely in fluid line, insisting that:
a Line or Lineament is not formed by Chance a Line is a Line in its Minutest Subdivision[s] Strait or Crooked It is Itself & Not Intermeasurable with or by any Thing Else Such is Job. (E784)
It has been supposed that, despite his opposition to Enlightenment principles, Blake arrived at a linear aesthetic that was in many ways more similar to the Neoclassical engravings of John Flaxman than to the works of the Romantics, with whom he is often classified.[102] However, Blake's relationship with Flaxman seems to have grown more distant after Blake's return from Felpham, and there are surviving letters between Flaxman and Hayley wherein Flaxman speaks ill of Blake's theories of art.[103] Blake further criticized Flaxman's styles and theories of art in his responses to criticism made against his print of Chaucer's Caunterbury Pilgrims in 1810.[104]
