difference between illusion and hallucination

We can usefully classify these theorists in terms of the magnitude and character of the difference that they posit between the two states. There are a range of theoretical options here that constitute an important choice point.Īll naïve realists hold that veridical experiences and hallucinations differ in some important way. Since there is no real prospect of analyzing hallucinations in terms of our being visually acquainted with physical objects, naïve realists must offer some other account of hallucinations. At least for present purposes, these claims define the naïve-realist position.Ī broad consequence of this position is that veridical conscious experience and hallucinatory conscious experience are importantly not the same. On this view, the subjective dimension of veridical experience is world-involving, consisting in a relation of acquaintance to external things. Further, he identifies the phenomenal character of veridical experience with the property of being visually acquainted with these external items. Fish characterizes the structure of veridical experience in terms of a subject being visually acquainted with a physical object and its perceptible properties. Nonetheless, the book as a whole is a clear presentation of an intriguing and comprehensive naïve-realist view, a work that sharpens our understanding of the debate to which this theory contributes.įish’s naïve realism makes claims about the structure and phenomenal character of veridical experience. Furthermore, I believe that Fish’s account of hallucinations faces serious problems. Turning to some criticisms, readers may want more positive motivation for naïve realism than Fish provides. His most extensive engagement with scientific work on perception comes in chapter 5, where he challenges the apparent empirical basis of some entrenched ideas about the phenomenal character of experience. Fish’s discussion of these topics often draws on relevant work from psychology. In filling out his naïve-realist account of perception, Fish addresses a wide range of topics of current interest in the field, including attention, conceptual and recognitional capacities, and the metaphysics of color. Fish communicates a clear sense of the philosophical landscape that naïve realists confront, and defends a stimulating proposal about how naïve realists should deal with key parts of this landscape. William Fish’s Perception, Hallucination, and Illusion is perhaps the first book-length defense of naïve realism and associated doctrines to appear as part of this new work. In the last ten years or so, a very sizeable new body of literature on naïve realism has quickly developed. The second newcomer, or returnee, is naïve realism.

The first is contemporary representationalism, advocated by Gilbert Harman, Michael Tye, and others. Recently two somewhat novel options in philosophy of perception have appeared, and indeed taken centre stage in the debate.

Two familiar theories in the philosophy of perception are the sense-datum theory and adverbialism, both of which were popular at different points during the twentieth century.

Difference between illusion and hallucination