In the theory of special relativity, the speed of light is considered to be a fundamental constant denoted by 'c.' It is postulated to have the same value regardless of the relative motion of observers. This means that the speed of light is constant in all inertial reference frames.
Changing the value of the speed of light would have significant implications for the entire framework of physics, including time dilation. However, in our current understanding of the universe, the speed of light is a fundamental constant that does not change.
Time dilation in special relativity arises from the fact that the speed of light is constant and independent of the relative motion of observers. It is a consequence of the spacetime geometry that emerges when considering the properties of light and the constancy of its speed.
If, hypothetically, the speed of light were to change, it would fundamentally alter our understanding of the universe, and the concepts of time dilation and other relativistic effects would need to be reevaluated. However, such a scenario is purely speculative and not supported by any scientific evidence or observations.
It's worth noting that the constant speed of light is one of the fundamental principles on which the theory of special relativity is built. It has been experimentally verified to an extraordinarily high degree of precision, and it forms the foundation for our current understanding of the behavior of space, time, and matter at high speeds.