Two fundamental concepts humans have defined to describe the world around them are spatial dimensions and time. These are human concepts, no other form of life on the planet utilizes them, cares about them, they are uniquely applied by humans trying to model and understand the physical world.
We define the concept of spatial dimensions to be height, width and length. In order to quantify those dimensions, a standard measure is required that also occupies those dimensions against which we can make a relative observation.
Early civilizations used the size of someone’s feet or the length of their arm. Eventually international standards were agreed upon such as the British Imperial and Metric systems. We have tools that encode those standard measurement systems like a ruler, a yardstick, a tape measure etc.
Einstein’s theory of relativity treats time as a ubiquitous, abstract phenomenon without form or description. Something that can only be measured but not seen or touched. I define the concept of time to be relative motion in spatial dimensions. Relative motion is essential for life like electrons around a nucleus, photons bombarding plants and nuclear fusion in the sun but it was humans who categorized those physical phenomena into the concept of time. Life did just fine for billions of years without a formal concept.
In order to quantify time, a standard measure of relative motion is required against which we can make an observation of other relative motion. Any relative motion between two inertial reference frames can be used. Early civilizations used sun dials to measure the relative motion of the earth with the sun by measuring the relative motion of a shadow with the face of the dial. Hour glasses use the relative motion of grains of sand from the top capsule to the bottom. Eventually international standards were agreed upon such as the Universal Coordinated Time (UCT). We have tools that encode UTC like a watch, a clock, a cell phone etc. A clock is a relative standard measure of time (relative motion) because the hands move relative to the face and to each other.
Time is a concept and concepts are not bendable, twistable, fungible or anything else you can do to something physical. Concepts are ideas, thoughts and time and spatial dimensions are concepts we use in order to communicate “where” and “when” effectively. A 15th century native American telling someone to meet him at the “big willow” when the “sun is directly overhead” is using the concepts of space and time in order to communicate effectively. So is telling someone to meet you at the “Hard Rock” at 2:00 PM. The concept of time makes sense since telling someone to meet you somewhere doesn’t do much good if you don’t specify when.
The theory of special relativity theorizes that time contracts which is why the speed of light is measured the same from any inertial frame of reference. But the motion of light relative to an inertial frame of reference defines a clock, a measure of time and if it is the same from all inertial frames of reference, then it defines a universal measure of time. A clock that naturally “adjusts” to relative motion to remain constant. A “God” clock.
This creates a logical fallacy. The special theory claims there is no universal measure of time so time is relative which is why the speed of light is constant as measured from any inertial reference frame. If the theory is correct, it explains the existence of a universal measure of time from any inertial reference frame which contradicts itself.