This article explores the "Circe" episode of Ulysses in the light of recent debates on hallucination in neurosciences and the philosophy of mind. Bridging the gap between these two fields, it offers an alternative to the traditionally vague definition of hallucination as an intuitively grasped experience which deviates from ordinary perception. Arguing that the technique of the episode is similar to phantasmagoria, a pre-cinematic genre whose deceptive nature foreshadows the shifting viewpoints of "Circe", and drawing on the works of Lev Vygotsky and Charles Fernyhough, it arrives at an integrated definition of the status of "hallucination" in art, which does justice to both its epistemological and narrative implications.