Miri Segal wrote her doctoral thesis on 'Hyperfinite Equivalence Relations and Forcing'. Before you try to figure out what sub-branch of post-Structuralist theory to file that under, it might help to learn that Segal received her Ph.D. in mathematics, not art theory. The 36-year-old Israeli artist came fairly recently to the making of art, but was unusually prepared: with canny ideas transplanted from tangential disciplines and a healthy epistemological interest in the nature of illusion, both optical and psychological. For her first solo show in New York, Segal studied the contradictions and paradoxes of perception, using seductive visual models and rounds of ocular game-playing.
Vapor - The Poetic Principle (1999), comprises video footage of a wind-blown tree projected onto the whirling blades of a standing industrial fan with its protective grille removed. This creates the dual sensation of an image that is cast visually upon an object that projects back physically in the form of wind: a sort of sensory feedback loop. Owing to the rotation of the fan blades, the moving image cannot be fixed everywhere simultaneously, generating the impression of an unstable three-dimensional volume emanating, aura-like, from the fan's surface. As projected light passes through the gaps between the rapidly spinning blades, an identical version of the tree appears on the wall directly behind. Analogous to a zoetrope device - a popular 19th-century amusement that produced a flickering moving image when light penetrated the slits in its rotating drum - the fan's stuttering surface causes a false doubling of what is actually a single image oscillating imperceptibly between fan and wall.
Our senses are often more persuasive than our reasoning mind. The disorienting perceptual closed circuit created by a two-dimensional representation of wind (the video) and its actual manifestation (the fan) amplifies the sensation of a third discrete element synthesized somewhere between the two. Hermann von Helmholtz, the 19th-century German pioneer in the psychophysiology of optics, wrote 'none of our sensations gives us anything more than "signs" for external objects and movements.' Optical illusions are troublesome for the very reason that they reshuffle the deck of those signs and their interpretation. Constructed tautologically, Vapor attains a certain rapturous lyricism - without sentiment or triteness - because Segal never tries to hide the simple mechanics of what remains a soothing sleight of hand.
A more technically elaborate musing on illusion, Foreshadowing (2001) uses complex modelling software to create and operate a synthetic image of a spinning roulette wheel. Screened high above viewers' heads, the wheel is intermittently overlaid by a seemingly random number, flashed so briefly as to be nearly subliminal, which none the less always reliably 'predicts' the winner. With each round the ostensibly chance-determined outcome of the game invariably fulfils the expectations of the tipped-off viewer. Segal's roulette wheel is not simply a rigged tool for suckering gamblers and museum-goers but is also an object of optical deception that, like the spinning hypnotist's spiral it resembles, is visually mesmerizing and suggestive. As it slows, the wheel appears to rotate forwards and backwards simultaneously, its retrograde motion both promising and teasingly denying the desired result. The artist shares a nimble intellectual curiosity in the trickery of optics with Duchamp, the self-styled 'precision oculist' whose dizzyingly pulsing rotoreliefs and demispheres optiques explored the same languid state of temporal suspension induced by the inward-turning spiral. For all its ambiguity the work seems to propose that the results of our actions may be far more predictable then we care to admit.
The image of the roulette wheel was screened in such a way that visitors could not avoid casting their shadows on the work. During a recent visit I noticed that my own shadow had been joined by another, whose impatient, weight-shifting body language silently communicated museum fatigue. Automatically glancing towards the new arrival, I discovered that if I remained alone in the gallery, the shadow became another chimerical overlay of projection. Thus gently duped, the viewer's sudden awareness of the artist's unaccountable presence (it is Segal's own phantom-like shadow) disrupts any stable suppositions about the relationship between observer and observed, making one keenly attentive to one's simultaneously participatory and voyeuristic position. In The Optical Unconscious (1993) Rosalind Krauss describes this 'both at once' sensation as 'being caught inside the illusion and looking on nonetheless from without'. The success of this or any other parlour trick is entirely dependent upon our willing desire to suspend disbelief and just play along.