# The beginnings of the thermal interpretation

I began to develop the thermal interpretation of quantum mechanics
from beginnings in a paper published in

referred to below as EEEQ, in discussions 2004-2007 on the German
newsgroup de.sci.physik (e.g.,
Ein Modelluniversum), from which I created a FAQ in German,
Die Thermische Interpretation der Quantenmechanik.
The entries in this FAQ were written in the years 2006 and 2007.
The following texts constitute the English translation.
Many thanks to David Nolland who translated the pages.
Some of the material is no longer up to date and should be interpreted
*cum grano salis*, in the light of the more accurate material
linked to above.
With time, I hope to go through the content of the entries below and
update it to fully reflect my current understanding.

The Thermal Interpretation
How best to read EEEQ
Core propositions of the thermal interpretation
Motivation for the thermal interpretation
The only observables of physics are expectation values
Two kinds of expectation values
The thermal and Copenhagen interpretations
Why has no one before me thought of this?
The measurement process in the quantum universe
The quantum universe as a formal model
A model universe
Physical systems and their measurement
Predictions in the Stern-Gerlach experiment
What happens to individual photons in the double-slit experiment?
The quantum eraser in the thermal interpretation
Does one have to know the state of the whole universe?
Can one falsify the state of the universe?
How can randomness be explained?
Is quantum mechanical randomness objective?
How should one understand probability distributions?
What becomes of the superposition principle?
Spin-measurement formally described
What is idealised in Wigner's analysis?
Collapse as conditional probability?
What are the beables of the interpretation?
What is an expectation value?
What is a preparation?
What is a microscopic measurement?
But can one really measure individual photons?
What is a photon?
Are there problems with locality and Bell's inequalities?
Are objective measurement values compatible with unitarity?
How hidden are hidden variables?

Arnold Neumaier (Arnold.Neumaier@univie.ac.at)