Unity in variety

Human brain needs the generally chaotic world to be structured for a better apperception, perceptual organization, and processing fluency, thus creating the want for unity, a holistic view enabled through perception of order and coherence between the parts of the whole.

From the neurophysiological point of view, perceiving unity underlying the collection of disparate objects economizes the capacity of the brain, reducing the allocation of attentional resources.

In the late 18th century Kant explained the feeling of beauty by "free play" of the human cognition, unshackled from the minutiae of reality and instead finding pleasure in a search of a unifying structure.

[8] The concept of unity in variety was first applied to the empirical aesthetics in the end of the 19th century by Gustav Fechner as the "principle of unitary connection of the manifold": humans "tolerate most often and for the longest time a certain medium degree of arousal, which makes them feel neither overstimulated nor dissatisfied by a lack of sufficient occupation".

[12] The end of the 20th century brought interest in precise definitions of unity and diversity, this purely cognitive analysis breaks with the Fechner's hedonistic approach.