Professor Fred Alan Wolf claims that consciousness is fundamental and not a product of the brain. He writes: "There is evidence that suggests the existence of a non-material, non-physical universe that has a reality even though it might not as yet be clearly perceptible to our senses and scientific instrumentation. When we consider out-of-body experiences, shamanic journeys, and lucid dream states, though they cannot be replicated in the true scientific sense, they also point to the existence of non-material dimensions of reality." (1998:245)