## 7 Conclusions
The paper shows that time measurement in kinematics is based on signal clocks and therefore is sensitive to the speed at which the clock moves relative to the medium in which it propagates the signal (STE) or at which the clock moves relative to the observer (STR). In modern relativistic, the time dilation, which is the property of signal clocks, has been automatically transferred to all other physical processes without proper justification. For example, it is not at all certain that biological processes (e.g., the twin paradox) are subject to the same time dilation as light clocks. This should only be verified experimentally. In this way, the idea of time was created, which is a space-time dimension that is not related to any specific physical processes. However, there is no reason to argue with certainty that the speed of the inertial system affects in the same way the frequency of all physical processes, according to time dilation. If the physical process has no relation to the signal clock, the duration of this process may not be subject to time dilation. For example, the life expectancy of a person may depend on the speed of movement in a different way than the speed of ticking (i.e., the period of ticking) of the atomic clock. For this reason, it is not known whether conventional twins, from the paradox of twins, will be subject to time dilation resulting from kinematics. Everything depends on whether the speed of life processes is correlated with the speed of the signal clock. Time dilation refers to signal clocks and physical processes that are related to the signal clock. In the case of other physical processes, the determination of whether they are subject to time dilation requires, in each case, experimental confirmation or some theoretical justification. From the analysis presented, it follows that time dilation can be interpreted as properties of a light clock and not a property of space-time, as is now believed in the Special Theory of Relativity. The article showed that the mathematics of STR could be interpreted differently than it is currently performed. According to the presented interpretation, the properties of time in STR result from the properties of the light clock (the theorem on the light clock). Since the light clock stops timing when it is accelerating to the speed \(c\) with respect to the observer, therefore the theoretical formulas stop working in inertial systems moving at speeds greater than or equal to \(c\). The formulas stop working not because the velocity \(c\) is impassable but because the light clocks are not working. It follows from this that the mistaken belief is that the speed of light in a vacuum is certainly the maximum speed in nature. So what results from STR mathematics depends on the adopted interpretation of this mathematics. One interpretation (now taken for granted) shows that speed \(c\) is the maximum speed in nature. However, the interpretation in this article only shows that in inertial systems moving at speed \(c\), light clocks do not work. Due to the lack of time measurement, it is not possible to describe the physical processes in these systems. It should be noted that scientific methods do not allow proving that something is impossible. Something may be impossible under some theory or under how this theory is interpreted at any given time. However, no theory is absolutely certain because perhaps, in the future, a phenomenon will be discovered which will undermine it. Science can only prove that something is possible if it is performed in a practical way. However, the criticism of \(c\) as a maximum speed presented in this paper is not based on this property of science. The paper shows that even under the Special Theory of Relativity, there are no grounds for treating \(c\) as a maximum speed. Even if \(c\) is the maximum speed in nature, it does not follow from the mathematics of Special Theory of Relativity as it is widely believed today.