It is difficult to find agreement on what constitutes perceiving. The term is used in a wide array of domains ranging from psychology to physiology to aesthetics, and over time it has also acquired diverse connotations within various disciplines. Current perceptual science, however,
even when it deals with qualitative aspects of experience, for example phenomena of lightness and colour, almost exclusively explains them in terms of primary qualities or stimuli quantitatively understood. The fact that science treats qualitative experiences in terms of stimuli is important,
because almost nothing of phenomenal perception as such is quantitative in nature. The paper argues for a qualitative science of perceiving, its methodology, its laws, and its possible developments.