INTERFERENCE, INTENTIONALITY, INCOMMENSURABILITY For Blake, the stray data that escape the repressive certainty of "Single Vi- sion" are keys to reno- vating the individual's perceptual structures. Revision as an ontologi- cally destabilizing action rather than a movement toward closure The presence of an implied world behind the text is progressively obliterated by The Four Zoas. crepancies between textual details merely reflect errors of perception or memory in characters or in the narrator. Both "Single vision" and "New- tonian narrative" aim toward realizing the coherence and completeness of a narrative world or text (which, in this view, contains a narrative world in potential form) and toward realizing a preordained "end" or closure that resolves conflicts into a unified whole.8 The implicit goal of Newtonian narrative is imaginative death through positive affirmation; the explicit goal of Blake's narrative is an intense awakening, through negative dialec- tic,9 to hitherto buried possibilities of the human imagination. The conflict between, on the one hand, Blake's desire to renovate his reader's perception by relentlessly subverting "Single vision," and, on the other, the powerful temptations of Newtonian narrative itself is played out in the radical process of revising that The Four Zoas underwent. At times, Blake's disruptive revisions seem almost an overreaction against his own Newtonian impulses, resulting in alien poetic strategies and narrative complexities that easily could be (and have been) taken as demonstrating incoherence or a loss of control and purpose.10 How the poem was trans- formed from its Vala state into The Four Zoas suggests that revision takes on a double significance: it is both something that Blake did to the text and something that the text does, through the agency of narrative, not only to the reader, but to itself. Indeed, Blake's whole enterprise constitutes the irreducible presence of multiple interfering and incommensurable struc- tures that operate 1) to rule out a pre-existent underlying world which surface events (i.e., those narrated by the linear text) partially rearrange and partially distort, and 2) to generate a narrative field in which the past is not finished and closed but incomplete and open-alterable and revisable. That is, instead of a prefabricated underlying single world or ur-narrative (whether it be an ideal substratum of the text or Vala itself) that supports the details of the surface narrative-is signified and re- arranged by them-Blake substitutes a transformational process at the service of (and brought into existence by) the temporally unfolding sur- face narrative itself. This continuously originary process retroactively resembles a deep structure in that, although characters and events come into existence the moment they are narrated (that is, they are not presup- posed or contained in any fashion, potential or otherwise, until they explicitly enter the poem), once characters and events come into existence they behave as if they belonged to an underlying world, one that is never articulated except through self-cancellation, but to which characters attempt to refer. In this sense, the surface narrative is primary, and what- ever deep structure there is emerges as an evolving secondary by-product of the operations of the poem's narrative surface." By incorporating into The Four Zoas subversive narrative processes (perspective transformation and aspectual interconnection) and textual features (text as flight and text as woven pattern), Blake achieves what otherwise might seem virtually impossible-a narrative field with an open past such that past narrative facts can be altered and revised by present ones, thereby allowing present