Before reading this post, please bear in mind that this post is not about physics. It is rather a philosophical reflection on the concept of time, as defined by physics.
With regards to time, my views are similar to those of Leibniz and Kant, who, according to Wikipedia, consider time as “part of a fundamental intellectual structure (together with space and number) within which humans sequence and compare events.”
My reasons for believing time to be more of an intellectual structure rather a part of the physical world much as chairs, tables and lamps stems, primarily, from my propensity for philosophical thinking as well as the definition of time provided by modern science.
For example, the SI definition of a second is as follows:
the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
According to this standard definition, a second is defined in terms of “duration of a fixed number of periods” making the whole definition of time extremely circular. What is a period? Nothing but time. The definition, therefore, according to my understanding, defines time in terms of time and fails to provide an independent physical referent for time.
Einstein said that “time is what a clock measures.” What does a clock measure?
A simple, analog clock measures time down to the smallest unit of a second. Each second is, in turn, measured in terms of the movement of the sweep hand between two second tick-marks on the face of the clock.
So, what becomes evident is that time is measured in terms of the observable movement of an object, be it the shadow on sundial, hands in analog clock or cesium atoms in an atomic clock.
It would seem erroneous, from the perspective of physics, to equate time with motion for motion is measured in terms of time. Time appears to have a physical correspondence with motion but is not the motion itself.
Time, itself, therefore, appears more of an intellectual construct having a physical correspondence with the movement of objects characterized by their change of position/state/spatial coordinates.
It is a useful intellectual construct insofar as it is used by humans to order and manage their lives. It definitely lacks a physical form similar to objects in the physical world such as trees, cars and buildings.