  The quantum theory of ur-objects proposed by C. F. von Weizsaecker has to be
interpreted as a quantum theory of information. Ur-objects, or urs, are thought
to be the simplest objects in quantum theory. Thus an ur is represented by a
two-dimensional Hilbert space with the universal symmetry group SU(2), and can
only be characterized as ''one bit of potential information''. In this sense it
is not a spatial but an ''information atom''. The physical structure of the ur
theory is reviewed, and the philosophical consequences of its interpretation as
an information theory are demonstrated by means of some important concepts of
physics such as time, space, entropy, energy, and matter, which in ur theory
appear to be directly connected with information as ''the'' fundamental
substance. This hopefully will help to provide a new understanding of the
concept of information.
