Niklas Luhmann
Almost everything in this site has been influenced, one way or another, by the texts of Niklas Luhmann.
This attempted approach to commence with decisions (and fundamentally, alongside, with differences), is, in its (socially focused) system-theory, an integrated principle. In order to observe something (e.g. light) we require contrast, which the observer always generates and also uses (light/dark). And as nothing is recognisable without differentiation, decisions are required about which difference one makes and uses in order to gain information. Luhmann has pursued this principle with unbelievable consistency, that everything takes its origin from observation and can be examined for differences which are then used, and has made it profitable for many field of knowledge The capability of this difference-theoretical principle is enormous. The breadth and depth of his concepts are, in many aspects, unexploited for other disciplines such as psychology and philosophy. The reading of his texts, for most people, must be undertaken and assimilated slowly. Those who take the trouble, will gain a treasure trove of inspiration which will last a lifetime.
Unbelievable.