The Spectre is one aspect of the fourfold nature of the human psyche along with Humanity, Emanation and Shadow that William Blake used to explore his spiritual mythology throughout his poetry and art. As one of Blake's elements of the psyche, Spectre takes on symbolic meaning when referred to throughout his poems. According to professor Joseph Hogan, "Spectre functions to define individuals from others [...] When it is separated [from Emanation], it is reason, trying to define everything in terms of unchanging essences."  Thus, according to Samuel Foster Damon, Spectre epitomizes "Reason separated from humanity" and "Self-centered selfhood" or, as Alexander S. Gourlay puts it, Spectre is "characterized by self-defensive rationalization".
Spectre appears in several of Blake's works, including Jerusalem, Milton: a poem and The Four Zoas. Because of its widespread presence in Blake's more mythological works, scholars have reflected on Spectre through multiple critical approaches including Jungian archetypal analysis, as a means of mapping Blake's mythology within intellectual history and within his own biographical experience.
In Blake's works
- I see the Four-fold Man, The Humanity in deadly sleep
- And its fallen Emanation, the Spectre and its cruel Shadow.
Elsewhere in Jerusalem, Blake defines it this way: "The Spectre is the Reasoning Power in Man, and when separated from Imagination and closing itself as in steel in a Ratio of Things of Memory, It thence frames Laws and Moralities [...]." The Spectre also appears in his published works Milton and The Four Zoas.
Historicist critics sometime look for direct inspirations for Blake's mythological ideas, such as Spectre, in his life experiences. In his 1966 article titled "Cowper as Blake's Spectre", Morton Paley argues that William Blake was thinking of the poet William Cowper, his philosophy and madness when creating the character of Spectre. In his argument, he discusses Blake's admiration and connections to Cowper both intellectually and socially as helping Blake create the archetype which became Spectre within the larger Blake mythology .
Some critics have used Blake's mythology to help map elements of his mythology within a larger intellectual history. For example, in his book Blake, Kierkegaard, and the Spectre of Dialectic, Lorraine Clark argues that Spectre and its relationship to Los signals a change in Blake approach to history and philosophy. He says that Blake in his focus on "the Los and Spectre in The Four Zoas, Milton and Jerusalem, Blake turns from a Hegelian "both-and" dialectic of Orc and Urizen in his earlier works to something very Kierkegaardian "either/or".
In general, Blake's mythology lends itself to psychoanalytic criticism, because of its clear archetypes. According to scholar Mark Ryan, the acclaimed literary critic Northrop Frye often aligned Spectre with persona in Jung's archetypes. On the other hand, Ryan says that many other critiques using archetypal approaches "tend to automatically relate the "Shadow" and the "Spectre," as pertaining to the concept of the dark side of the psyche, without considering the possibility that each character's shadow is, by implication, open to different modes of interpretation."
- For a transcription of the poem see it on Wikisource
- "Copy Information for Jerusalem The Emanation of The Giant Albion". William Blake Archive. Retrieved Sep 11, 2013.
- Morris Eaves, Robert N. Essick, and Joseph Viscomi (ed.). "Object description for"Jerusalem The Emanation of The Giant Albion, copy E, object 15 (Bentley 15, Erdman 15, Keynes 15)"". William Blake Archive. Retrieved September 12, 2013.
- Hogan, Joseph. "Glossary". The Urizen Books of William Blake. Department of Languages and Literatures, University of Wisconsin-Whitewater.
- Damon, Samuel Foster (1988). "Spectre". In Morris Eaves. A Blake Dictionary: The Ideas and Symbols of William Blake. UPNE. pp. 380–382. ISBN 9780874514360.
- Gourlay, Alexander S. Morris Eaves, Robert N. Essick, and Joseph Viscomi, eds. "An Emergency Online Glossary of Terms, Names, and Concepts in Blake". William Blake Archive. Retrieved September 26, 2013.
- William Blake. Morris Eaves, Robert N. Essick, and Joseph Viscomi, ed. "Transcription of "Jerusalem The Emanation of The Giant Albion, copy E, object 15 (Bentley 15, Erdman 15, Keynes 15)"". William Blake Archive. Retrieved September 12, 2013.
- William Blake. Morris Eaves, Robert N. Essick, and Joseph Viscomi, ed. "Transcription of "Jerusalem The Emanation of The Giant Albion, copy E, object 74 (Bentley 74, Erdman 74, Keynes 74)"". William Blake Archive. Retrieved September 12, 2013.
- Paley, Morton D. (Spring 1968). "Cowper as Blake's Spectre". Eighteenth-Century Studies 1 (3): 236–252.
- Clark, Lorraine (2009). Blake, Kierkegaard, and the Spectre of Dialectic. Cambridge University Press. ISBN 9780521110471.
- Ryan, Mark (June 2011). "Fearful symmetries: William Blake, Northrop Frye, and archetypal criticism". English Studies in Canada 37 (2): 173. Accessed via Academic OneFile (subscription required)
- Rose, Edward J. (June 1977). "Blake and the Double: The Spectre as Doppelganger". Colby Quarterly 13 (2).