If a stone rolls down a hill, we would say it is simply following the law of gravitation. It is not “going somewhere” as if it had a destination – that would require nature to have a soul, a view that died out in the early modern period. But if a person or an animal or even a seed pod moves down a hill, we expect it to be going somewhere, to have a destination or purpose.
That is the difference between a subject in motion and an object in motion. At a minimum, an object must have some starting point, at least from our observation, but need not have a destination or purpose for all we know. On the other hand, a subject need not have a known starting point but at a minimum there must be some movement toward a destination or end, else they would not be a subject.
This simple difference leads to a different formulation of space, time, and matter for subjects and objects. Modern physics has been entirely focused on bodies as objects, particles, or waves. In contrast, the physics of subjects will focus on bodies as subjects (somebodies), tempicles, and networks.
Since there is a destination, something about its location must be known. At a minimum there must exist a route or path for the subject to traverse to reach their destination. Even if the length of the path is not known, one can at least measure the progress made toward reaching the destination by measuring the space rate of movement, called the pace.
The difference between speed, the time rate of motion, and the pace is the difference between taking space or time as the independent variable. For objects their motion from an instant is what is given and so time is the independent variable. For subjects space is the independent variable since their movement toward a spatial destination is given.
That means for subjects the dependent variable is time, which is measured along with the direction of movement, which results in three dimensions of time. Space is confined to the path of movement, which may be rectified as a line for linear referencing. Examples of a linear reference are the milepoint (MP) and kilometric point (PK) on a map or sign.
Objects have chronologies. Subjects have a destinations. But subjects are like objects in some ways, and objects are like subjects in some ways. For example, a projectile is an object that has been launched by a subject toward a destination.
Mechanistic sciences such as physics study objects. Teleological sciences such as economics study subjects. The physics of subjects is physics for the social sciences.
For more, see the other posts on this website about time-space, with 3D time and 1D space.