Impossible objects such as the Necker cube above are drawings that appear as two different objects, in this case either a box standing out toward the lower left or toward the upper right. It can be seen as one or the other but not both simultaneously.
3D space and 3D time are like this. One can see either 3D space or 3D time but not both simultaneously. One may develop a unified 6D geometry for both of them but to measure rates either space or time must be reduced to a scalar or 1D quantity.
It is the same with observation and transportation. One can view a motion from the perspective of an observer (whether one is moving or on the sidelines) or from the perspective of a traveler (whether one is traveling or on the sidelines).
The observer sees motion taking place in 3D space ordered by scalar time. The traveler sees motion taking place in 3D time ordered by scalar space, that is, the stations.
The picture above represents what an observer might see but also what a fan might notice: that car 83 is pulling ahead of car 53. A generic observer just sees two cars in motion but a fan looks at who’s in the lead and how close they are to the finish line.
These two ways of seeing reflect the rôle of the person seeing:
The observer is a bystander or someone who happens to be in motion without considering where they’ve coming from or where they’re going to. It’s a disinterested rôle focused on the present in a synchronic description of motion.
The traveler is a participant or someone who is concerned about the motion so that where they are now is connected to the place they’re coming from and the destination they’re going to. It’s an interested rôle focused on the future more than the present in a diachronic description of movement.
The science of material and mechanistic causes is synchronic because it emphasizes the detached observer focused on each present. A science of formal and final causes focuses on the origin and destination of travelers. For example, diachronic linguistics looks at where languages have come from and where they’re trending toward.
One can also see this difference in the Galileo-Newton physics of the observer compared with a complementary physics of the traveler. The difference is between taking the speed of light as either moving instantaneously toward an observer or going instantaneously away from a transmitter toward a destination.