  We attempt to contribute some novel points of view to the "foundations of
quantum mechanics", using mathematical tools from "quantum probability theory"
(such as the theory of operator algebras). We first introduce an abstract
algebraic framework for the formulation of mathematical models of physical
systems that is general enough to encompass classical and quantum mechanical
models. After a short discussion on the properties of classical systems
(realism and determinism), we move on to the study of a general class of
quantum-mechanical models of physical systems and explain what some of the key
problems in a quantum theory of observations and measurements are. In the last
part of our essay, we attempt to elucidate the roles played by entanglement
between a system and its environment and of information loss in understanding
"decoherence" and "dephasing", which are key mechanisms in a quantum theory of
measurements and experiments. We also discuss the problem of "time in quantum
mechanics" and sketch an answer to the question when an experiment can be
considered to have been completed successfully.
