We take as given the idea of distinction and the idea of indication, and that we cannot make an indication without drawing a distinction...
A distinction is drawn by arranging a boundary with separate sides so that a point on one side cannot reach the other side without crossing the boundary. For example, in a plane space a circle draws a disctinction.
Once a distinction is drawn the spaces, states, or contents on each side of the boundary, being distinct, can be indicated.
Maturana and Varela, 1987, p.40
A unity (entity, object) is brought forth by an act of distinction. Conversely, each time we refer to a unity in our descriptions, we are implying the operation of distinction that defines it and makes it possible.
If one wants to thematise the unity of a difference, one must determine both sides of the distinction. It would be pointless to confront something determinate with something entirely indeterminate, and therefore nobody does it... With the help of this technique, one can deal with differences as unities, can decide whether one is dealing with health/ illness or with something else.
Perception operates only upon difference. A receipt of information is necessarily the receipt of news of difference, an all perception of difference is limited by threshold. Differences that are too slight or too slowly presented are not perceivable. They are not food for perception.
It takes at least two somethings to create a difference. To produce
news of difference i.e. information, there must be two entities (real or
imagined) such that the difference between them can be immanent in their
mutual relationship.