Visibility paradox means that the arrangement of elements in which metric segregation is maximised, that is, the linear shape, is also the arrangement in which visual integration is maximised. For example, If all elements are arranged in a straight linear line, the visible integration of the form is maximised because all the elements can be covered by a single sight line; however, the metric integration is minimised because the metric distance from all elements to all others is minimised.
Visibility paradox
Sources
Hillier, B. (1996, 2007), Space is the Machine: A Configurational Theory of Architecture. Space Syntax: London, UK. pp. 266-267