  This paper constitutes a background to the paper 'Quantum mechanics as
"space-time statistical mechanics"?', arXiv:quant-ph/0501133, presented
previously by the author. But it is also a free-standing and self-contained
paper. The purpose of this paper is to give the reader an increased and a
deeper understanding of the special theory of relativity, and the spacetime
ideas lying behind the above mentioned paper. We will here consider, discuss,
define, analyse, and explain things such as, e.g., the constancy of the speed
of light, synchronization, simultaneity, absolute simultaneity, absolute space
and time, the ether, and spacetime. Albert Einstein's original version of the
special theory of relativity is fundamentally an operational theory, free from
interpretation. But the old "Lorentzian interpretation" and the standard
"spacetime interpretation" of the special theory of relativity will also be
considered. This paper also discusses and analyses aspects of the philosophy of
science that in my opinion are relevant for an understanding of the special
theory of relativity.
