I’ve written about the inverse perspectives of travelers and shippers versus observers and scientists *here*. This post focuses on the language used, primarily the expectation of what motions larger or smaller values of measures correspond to.

For an observer we’re accustomed to larger values corresponding to faster, more powerful motions. But travelers are usually trying to minimize something such as the time or energy expended. So smaller values correspond to faster, more powerful movements.

Terms should follow these expectations. Speed is faster as its magnitude increases and slower as its magnitude decreases. Pace is the opposite of this. Pace is faster as its magnitude decreases and slower as its magnitude increases.

The term for pace with direction should be similar: it is a measure of motion that decreases with faster movements and increases with slower movements. This is counter-intuitive at first but fits the pattern of an inverse perspective.

I will revise the terms I have used to be consistent with this understanding. New terms:

celerity – pace with direction; values closer to zero indicate faster pace. [was lenticity]

celentum – celerity divided by mass (or times vass); values closer to zero indicate faster motion or smaller mass [was prolentum]

surge – prestination divided by the mass (or times the vass); smaller values indicate larger force [was gorce, elaphrence, mollence, egeirence or visity]

prestination – rate of celerity; positive values indicate pace becoming closer to zero [was relentation or retardation]

vass – inverse of mass

See the *Time-Space Glossary* above.