The book rests on advanced concepts central to systems theory and semiology, i.e. Niklas Luhmann's theory of the structural link between consciousness and communication and C.S. Peirce's triadic theory of signs. Emphasis is placed on the structural similarities between these theories, notably in the triadic models they advance, similarities observable both in autopoiesis and semiosis. The reason for this emphasis is the new light it casts on venerable and fundamental issues in the theory of science and philosophy, notably the debate about world, truth and subject.