by Niklas Luhmann

The source of a distinction's guaranteeing reality lies in its own operative unity. It is, however, precisely as this unity that the distinction cannot be observed--except by means of another distinction which then assumes the function of a guarantor of reality. Another way of expressing this is to say the operation emerges simultaneously with the world which as a result remains cognitively unapproachable to the operation. The conclusion to be drawn from this is that the connection with the reality of the external world is established by the blind spot of the cognitive operation. Reality is what one does not perceive when one perceives it.

Extract from 'Roland Barthes by Roland Barthes', page 46