  We propose a system of information-theoretic axioms from which we derive the
formalism of quantum theory. Part I is devoted to the conceptual foundations of
the information-theoretic approach. We argue that this approach belongs to the
epistemological framework depicted as a loop of existences. In Part II we
derive the quantum formalism from information-theoretic axioms and we analyze
the twofold role of observer as physical system and as informational agent.
Quantum logical techniques are then introduced, and we prove theorems
reconstructing elements of the formalism. In Part III, we introduce the
formalism of C*-algebras and give it an information theoretic interpretation.
We analyze the conceptual underpinnings of the theory of modular automorphisms
and we give an information-theoretic justification for the emergence of time in
the algebraic approach. We conclude by giving a list of open questions,
including topics in cognitive science, decision theory, and information
technology.
