Human Made Laws of Physics as Standards

Recent posts have analysed the basic Postulate of modern physics in the form of the Special Theory of Relativity SR, which can be formulated:

• The speed of light in all inertial systems is the same.   (P)  

(P) is put into practice in the 2019 SI Standard compelling every human observer to measure distance in the Euclidean coordinate system being used by the observer in terms of travel time of light with a preset speed of light of 299792458 meter/second with time measured by a standard caesium clock. It is assumed that the different coordinate systems being used move with constant velocity with respect to each other, i. e. that so called inertial systems are used. 

(P) can be viewed as a human made operational definition/standard: The length scale in each inertial system is determined by actually measuring travel time of light in the inertial system and then setting the spatial scale according to a preset speed of light, e.g. using a standard rangefinder.

All observers will then agree that the speed of light is exactly 299792458 meter/second as a consequence of a human made operational standard. It would be silly to ask why all observers agree, when it is simply an agreement to agree, like a form of conspiration if you like. 

The next question is how well the 2019 SI Standard will work in practice in the sense that observations in different inertial systems can be coordinated. 

The first thing to say is that it is reasonable to expect that the speed of light will be the same in all inertial systems under the assumption that the same Maxwell's equations for light propagation are valid in all inertial systems. This may appear reasonable if you envision a many-aether system with each inertial system representing an aether medium for propagation of light according to Maxwell's equations formulated in the inertial system at hand assuming the observer is not moving with respect to the system. This is the vision of Many-Minds Relativity. 

But the task of coordinating observations in different inertial systems following the 2019 SI Standard remains, and this is not completely obvious and so the subject of Many-Minds Relativity.

We thus come to the conclusion that (P) appears as a human made law of physics, which will have to be confronted with laws of real physics when seeking to coordinate observations in different inertial systems.

We may compare with Newton's 2nd Law $f=ma$ with $f$ force, $m$ mass and $a$ acceleration, which can be taken as definition of one of the variables in terms of the two other, and then will have the form of a human made law of physics and so will have to be confronted with real physics with independent specifications of the variables.   

More generally we may compare with laws of physics in the form of conservation laws, such as

• Conservation of mass.
• Conservation of momentum (Newton's 2nd Law).
• Conservation of energy.

It is natural to view these as laws of physics corresponding to observations of systems being persistent over time, which neither blow up to infinity nor vanish to zero and so contain conserved quantities. 

We recall that Newton's law of gravitational force is a consequence of conservation of a conservative force. 

But there is also room for an aspect of human made laws, in the sense that whatever appears to be missing is contributed as a new phenomenon. For example, the observed loss of kinetic energy in turbulent flow is viewed to show up as internal energy (of unspecified form) thus maintaining conservation of energy.