To the Reader:
     When the "quantum medium view" was first reviewed, the reaction was, "We already have a sound theory (i.e. relativity theory) so why look for another theory?" This reaction reflects the prevailing belief that relativity theory (particularly special relativity) has been "proven." The reader will find below why this belief is false. The quantum medium view sheds light on the "soundness" of relativity theory. It shows that a theory's soundness does not depend only on it's consistency with experimental evidence. It shows that the "constant speed of light postulate," an assumption on which relativity theory rests, is probably false. After reading this document, the reader will understand why it is possible, if not probable, that the postulate is false. True, direct experimental evidence supports the prevailing belief that the speed of light is always the same in every observer's frame of reference. But the history of science shows that direct experimental observations often are misleading. It is easy to forget that our distant ancestors (who surely were very smart and passed on this intelligence to us) were certain that the sun moved around Earth -- because that is what direct observations showed.
     The view described in this paper is not only consistent with direct experimental evidence, it is consistent with historical evidence, and with logic. This paper will show why it is logical that the speed of light has been observed to be constant, why a clock that makes a round trip shows less elapsed time than an identical clock that does not make the trip, and why relativity theory has been controversial and confusing in spite of its usefulness.

Suggestions for reading this document.
     This document contains figures and simple equations which are referred to throughout the text. The equations are numbered in the order in which they are introduced. They also appear on an EQUATIONS page which is listed at the end of the Contents. The reader may find it helpful to print the page of equations and refer to it when equation numbers appear in the text.
     It will also help to have a second web browser window in which the figures can be displayed. Therefore, when Figure 1 is introduced the reader can click on the Figure 1 hyperlink which will open a second window. (If the second window covers the text window, decrease the window size so that both windows are visible.) This will avoid having to constantly open and close text and figure windows. Or, simply print the figures when they are introduced in the text.
     This document contains new terms which are necessary for making it clear and unambiguous. Most of these terms appear in the GLOSSARY which can be reached via the Contents page.
     A number of hypertext links appear in this document (e.g. "confusing" above). These links lead to information that will help the reader understand this document.