Perspectives on space and time

Space and time are complementary aspects of movement. Although space has been associated with stasis and time with change, they both entail movement. Space is the distance side of movement and time is the duration side.

There are two ways of looking at movement: one is from the perspective on or within the moving object and the other is from the perspective outside the moving object. The latter perspective observes the movement within a three-dimensional framework; the former perspective observes movement from within, along its one-dimensional path.

A system of synchronized clocks allows time to be one-dimensional. If clocks measured distance, say the circumference swept out by a rotating arm, then space could be one-dimensional, whatever distance the arm pointed to. Apart from such a system of coordinated movements, space and time are external, the framework within which movement takes place, which is three-dimensional.

Although relativity makes the internal and external perspectives formally the same, they are different ways of looking at the movement of an object. The inner perspective is like a passenger in a vehicle and the outer perspective is like a passenger watching a train arrive.


When moderns look at the sky, people see space, “outer space”. The modern perspective has one-dimensional temporal paths within a three-dimensional spatial framework. Maps and models allow one to locate things within this framework.

In ancient times only one clock existed — the heavens. People didn’t look down at their watches for the time, they looked up to the sky. Time was out there. Clocks make internal time easier to tell, time apart from the sky, although the sky may be used to calibrate a clock.

There was a time when maps didn’t exist, or at least accurate ones. The location of a place was given in relation to other places rather than in terms of a global datum or standard reference.

The ancient perspective has one-dimensional spatial paths within a three-dimensional temporal framework. Ancient geocentricity was temporal: heavenly bodies move around the earth. When looking at the sky, ancients saw time, “outer time” one might say.

Over the centuries geocentricity became more and more spatial: celestial spheres surrounding the earth in space. This was rejected in favor of a sun-centered system, and later an acentric space-time.