This chapter considers Eliot’s rendering of light as a dissembling vision, filtered through the evolving medium of the eye. Nineteenth-century experiments on the eye fed into Darwin’s theory of evolution and contributed to the nascent science of cognitive psychology. Captured by the post-Darwinian fascination with the origin of the human in the ‘protozoic slime’, Eliot’s poetry finds in the floating world of the eye a potent metaphor for the solipsism and atavism of artistic creation. The eye became for Eliot an increasingly contested symbol of empirical vision and its opposite—the inner vision, which may or may not reveal the ‘truth’ the eye conceals. The analysis extends from the eye to vision (in parallel with the movement from depictions of the physical eye to psychological symbols of inner vision), considering Eliot’s wavering between imagining the universal aspect of vision, and an awareness of the propensity for vision to play tricks with the spectres and shadows of its own casting. Robert Waring Darwin’s empirical studies of colour vision, Étienne-Gaspard Robert’s magic lantern shows, Dantean phantasmagoria, and Coleridgean spectres populate this chapter.