Nothing that can be said is independent of us. Whatever can be said is coloured by our dreams and aspirations, by the way our brain works, by human nature and human culture. Whoever claims to know or to observe is - according to the central constructivist assumption - inescapably biased. This book presents the views of the founders of constructivism and modern systems theory, who are still providing stimulating cues for international scientific debate. The conversations of Heinz von Foerster, Ernst von Glasersfeld, Humberto R. Maturana, Francisco J. Varela, Gerhard Roth, Siegfried J. Schmidt, Helm Stierlin, and Paul Watzlawick with Bernhard Poerksen, display a kind of thinking that steers clear of rigid fixation and reveals the ideal of objectivity to be a myth. The conversations turn on the results of brain research, the breaks through of cybernetics, the linguistic determination of thought, and the intrinsic connection between epistemology and ethical practice. Throughout, the central figure of the observer is examined with sophisticated wit and just enough irritating grit to create the pearl in the oyster. Constructivism thus emerges as a philosophy of possibilities that keeps generating new points of view, insists on fundamental scepticism with regard to certainties and dogmas, and provides the foundation for an ethics of perception: Each and every one of us is responsible for their view of things.