Why Is the Issue of the Nature of Spacetime So Important?

Abstract

For physicists, the answer to the question in this chapter’s title is twofold: In view of the multi-dimensional spaces of modern physics, it appears quite natural to address the question of the nature of spacetime first. If the world is indeed four-dimensional, in which macroscopic physical bodies are worldtubes or worldlines (in the case of small particles), Minkowski’s program – that physical laws might find their most perfect expression as relations between worldlines – should be pursued more rigorously. How Minkowski’s idea provides a deeper understanding of physical phenomena will be demonstrated in Part III of the book, and especially in Chap. 9, where inertia will be regarded as originating from a four-dimensional stress which arises in the deformed worldtube of an accelerated body.