Reference: Einstein’s 1920 Book
This paper presents Appendix 2 from the book RELATIVITY: THE SPECIAL AND GENERAL THEORY by A. EINSTEIN. The contents are from the original publication of this book by Henry Holt and Company, New York (1920).
The paragraphs of the original material (in black) are accompanied by brief comments (in color) based on the present understanding. Feedback on these comments is appreciated.
The heading below is linked to the original materials.
.
Minkowski’s Four-Dimensional Space (“World”)
Please see Appendix 2 at the link above.
.
The math of Minkowski’s World is based on the following consideration:
The fourth dimension is generally interpreted as the dimension of time. But from the earlier comments it appears that it should be interpreted as the dimension of the DURATION of substance. This is the dimension of inertia.
The first three dimensions are generally interpreted as the dimensions of space. But it now appears that they should be interpreted as the dimensions of the EXTENTS of substance. These are the dimensions of the substance as quanta, which are taken as an abstract point for matter.
We may say that x, y, and z are the dimensions of what we have been considering as a dimensionless point in space for matter.
.
