Relativity - The Special and General Theory, Albert Einstein [best ereader for academics txt] 📗

*** A refinement and modification of these views does not becomenecessary until we come to deal with the general theory of relativity,treated in the second part of this book.

SPACE AND TIME IN CLASSICAL MECHANICS

The purpose of mechanics is to describe how bodies change theirposition in space with "time." I should load my conscience with gravesins against the sacred spirit of lucidity were I to formulate theaims of mechanics in this way, without serious reflection and detailedexplanations. Let us proceed to disclose these sins.

It is not clear what is to be understood here by "position" and"space." I stand at the window of a railway carriage which istravelling uniformly, and drop a stone on the embankment, withoutthrowing it. Then, disregarding the influence of the air resistance, Isee the stone descend in a straight line. A pedestrian who observesthe misdeed from the footpath notices th