WikiMechanics

This is not a radical proposition. A central concept in science is that all evidence must be empirical. So surely it is reasonable for our theories to methodically consider sensation. But actually starting a presentation of physics this way may fit awkwardly with some commonly held views. Accordingly, the premise is discussed further here. In fact, most presentations of mechanics start with mysteriously received notions of length, time and mass. For example, a textbook that has been well-used for the last 80 years, Goldstein's Classical Mechanics begins by saying "they will be assumed as undefined terms whose meanings are familiar to the reader".¹ Traditionally, physics students are just supposed to know what length, time and mass are without any instruction! We learn very little about their origins even though they are very important concepts that physicists use every day of their working lives. Gaining a deeper understanding of these fundamental ideas is big part of what this wiki is for.