- is a consequence of quantum theory that affects virtually
**all**physical systems - arises from unavoidable interaction of these systems with their natural environment
- explains why macroscopic systems
*seem*to possess their familiar classical properties**No additional classical concepts are required for a consistent quantum description** - explains why certain microscopic objects ("particles")
*seem*to be localized in space**There are no particles** - explains why microscopic systems are usually found in their energy eigenstates (and therefore
*seem*to jump between them)**There are no quantum jumps** - thus explains why there appeared to be contradictory levels of description in physics (classical and quantum)
**There is but****ONE**basic framework for all physical theories: quantum theory - explains also how the Schrödinger equation of general relativity (the Wheeler-DeWitt equation) may describe the
*appearance*of time in spite of being time-less**There is no time at a fundamental level** - is a direct consequence of the Schrödinger equation, but has nonetheless been essentially overlooked during the first 50 years of quantum theory

Decoherence is the theory of ** universal entanglement**. Generically, it does **not** describe a distortion of the system by the environment, but rather a disturbance (change of state) *of the environment by the system*. This may nonetheless affect the system itself because of the fundamental quantum aspect of *kinematical nonlocality*.

The process of decoherence is based on an arrow of time in the form of a special (ultimately cosmological) initial condition.

Decoherence can *not* explain quantum probabilities without
(a) introducing a novel definition of observer systems in quantum
mechanical terms (this is usually done tacitly in classical terms), and
(b) *postulating* the required probability measure (according to
the Hilbert space norm).