Time is a strange concept according to several strains of science and related philosophical concerns. We have this everyday medium-macroscopic set of ideas about how there is an undiscovered country of the future, a now we are experiencing, and a past that we remember or model based on accumulated historical facts. When we venture into extensions of conceptual ideas like an infinite past or sequenced events we deploy reasoning about what their properties might be by excluding contradictory compositions of properties and using other kinds of limiting semantics to constrain a mental model of those concepts.

But that isn’t the weirder stuff. The weirder stuff is the result of a collision of measurement and scientific theory.

Take, for instance, the oft-described reversibility of Newtonian physics. We have an equation for an object’s motion that can be run backward in time. But entropy in large ensembles of things in motion is not reversible because of some odd property of energy dissipation into the environment that arises because of micro-interactions. Some say this creates an “arrow of time” in the face of these reversible equations.

But this is an odd way of characterizing mathematical statements that represent the uniformity of physical interactions. The idea of “reversibility” is just a matter of a computational representation of processes that do always flow forward in time. Running t from 0 to -∞ in an equation has no real relationship to any physical phenomena. So the reversibility of mathematical forms is just an interesting fact.

We can bind up space and time, as well, which also provokes feelings of incongruity when we start to talk about gravitational effects on relative elapsed time, or relative speed effects.… Read the rest