Here are a few places:
This was found in Blake's Primer:
The word strongly suggests reason, the primary quality of Urizen. Blake felt that the hegemony of rational thinking since The Enlightment had had a stultifying and destructive influence on the British culture. He chose Bacon, Newton and Locke to epitomize that destructive influence. He chose Urizen to exemplify it in his myth.
At the final consummation Blake rehabilitated Bacon, Newton and Locke. They appeared counterbalancing Blake's three great poets.
The Druid Spectre was Annihilate loud thundring rejoicing terrific vanishing J98.7; E257| Fourfold Annihilation & at the clangor of the Arrows of Intellect J98.8; E257| The innumerable Chariots of the Almighty appeard in Heaven J98.9; E257| And Bacon & Newton & Locke, & Milton & Shakspear & Chaucer (Jerusalem 98: 6-9 )
In Night II of The Four Zoas Urizen lost his faith and in vision saw the world collapsing into darkness:
FZ2: 23:9-24.8; (314)
This is found in this blog.
In Globes of Fire II we read:
"Los, the Imagination, carries his globe of fire to provide light and energy to the intuitive mind which discerns the spiritual dimension. Urizen is likewise endowed with a globe of fire so that the mind might reason and understand through the intellect. No light is brighter than that of the Eternal Urizen before the fall. The role of reason is preeminent until Urizen, the Prince of Light, refuses to accept the role of guide to the newly created man.
Urizen continues to carry his globe of fire after his fall into the dark abyss. His fate is to explore with a dim light which leads him into erroneous pathways. He substitutes his books of descriptions and laws for his faith in the ever expanding light.
It was Blake's belief that if man's ability to reason led him to depend on his own powers to give structure and meaning to the world, he was sorely deceived. Reason is capable of discerning and manipulating the finite and material; Intuition or Imagination sees the Infinite and Eternal.
From Blake's Book of Urizen:
Book of Urizen, Plate 20, (E 81)
"1. Urizen explor'd his dens
Mountain, moor, & wilderness,
With a globe of fire lighting his journey
A fearful journey, annoy'd
By cruel enormities: forms