Section 1.5 addresses the objection that consciousness is an illusion, and that the neurophysiological representation can be far more abstracted than its corresponding conscious experience. This is perhaps the most common objection to the principle of isomorphism, so it must be addressed in a paper whose central theme is isomorphism.

Section 2.2 shows how the problem of brightness contrast and brightness assimilation can be approached by introducing an explicit representation of the illuminance percept, as an example of how isomorphism would be applied to a classical problem in perception. I do not believe the reader would have thought of this solution even if he had understood the concept of isomorphism as described up to that point, which is why this example is so important, since it demonstrates that even so abstract and etherial a concept as a percept of illumination should be subject to isomorphism, if it is seen as a component of the subjective percept.

More importantly, this three-layer model is then used to explain in detail how the combination between isomorphism and multistability in perception together suggest that when a multistable percept flips to an alternative perceptual state, the complete perceptual images also flip, each one being completely reconstructed or reified in the new perceptual image. (This process is elaborated in the new draft). This central concept would be far more difficult to explain in the more complex fully spatial model, where the point-for-point competition between alternative percepts occurs in three dimensions in the volume of the sphere.

Finally, the same concept of a reified distinction between the lightness, brightness, and illuminance percept forms a central part of the more complete 3-D model, which again would be much more difficult to introduce in that more complex spatial model. The concepts embodied in this model therefore are introduced progressively, describing first the principle of isomorphism, then how it relates to brightness perception, then how this relates to multistability, then how the model incorporates full spatial perception, then amodal perception and perception outside of the visual field. Again, these ideas are elaborated in the new draft of the paper. Elimination of any stage in this progressive exposition would leave a gap in the explanation.