In some scholarly communities, such as cognitive psychology and computational neuroscience, gestalt theories of perception are criticized for being "descriptive" rather than "explanatory" in nature. For this reason, they are viewed by some as redundant or uninformative. For example, a textbook on visual perception states that, "The physiological theory of the gestaltists has fallen by the wayside, leaving us with a set of descriptive principles, but without a model of perceptual processing. Indeed, some of their 'laws' of perceptual organisation today sound vague and inadequate. What is meant by a 'good' or 'simple' shape, for example?"