Einstein and the Crisis of Theoretical Physics

The crown jewels of modern theoretical physics are the electronic computer and the atomic bomb. In the light of these amazing achievements it is surprising that theoretical physics today is in a state of crisis because it does not deliver anything useful anymore, only increasingly wild speculations way beyond experimental verification. 

Modern theoretical physics is thus today in a state of confusion and it is natural to seek the origin of the confusion, in order to dismantle it and so return to rationality as the leading principle of classical physics. 

The departure form rationality was initiated by Einstein in 1905 with his Special Theory SR of starting from the following dictate (also called postulate): 

• The speed of light is (must be) the same for all observes moving with constant velocity with respect to each other, that is for all inertial observers.        

Einstein would have been pleased to find that his dictate was adopted by International System of Units (SI) in 2019 as a new definition of the length unit of meter as the distance traveled by light (in vacuum) during $\frac{1}{299792458}$ of a second, or what is the same: 

• The speed of light is exactly $299792458$ meter per second. 

We understand that a scientific standard such as the new SI meter standard, is an agreement made by scientists, like agreeing that there are 100 centimetres on a meter, which is to be compared with a scientific fact. The validity of a standard cannot be verified or disproved by a physical experiment: An experiment verifying that there are 100 centimeters on a meter, would not be possible to publish in a scientific journal. The referees would point out that such an experiment would be based on a misunderstanding of the relation between meter and centimeter. 

For the same reason, a new experiment showing that the speed of light is exactly $299792458$ meter per second would be met in the same way. It means that all observers are required to adjust their length scale to meet this standard, and the real question (answered in Many Minds Relativity) is to what extent different observers will be able to agree when using this standard. 

From his dictate about the speed of light, Einstein developed SR as a new form of relativistic mechanics with all sorts of new strange phenomena such as time dilation, space contraction, relativistic mass, fundamentally different from Newtonian Mechanics NM. 

NM was the ultimate expression of classical physics capturing all of mechanics including gravitation in the following precise mathematical terms as a Model of Newtonian Mechanics MNM:  

• $\rho=\Delta\phi$                                     (conservation of gravitational force)
• $\dot\rho +\nabla\cdot m =0$                        (conservation of mass)
• $\dot m +\nabla\cdot (um) +\rho\nabla\phi =0$    (conservation of momentum)

describing a (zero pressure for simplicity) distribution of matter subject to gravitation, where $\rho$ is mass density, $\phi$ gravitational potential, $\nabla\phi$ gravitational force per unit mass, $m$ is momentum, and $u=\frac{m}{\rho}$ is material velocity, all depending on a Euclidean spatial coordinate plus time with the dot representing differentiation with respect to time. MNM expresses the same physics in all inertial systems and so is a form of Galilean invariant relativistic mechanics perfectible compatible with the 2019 SI Standard of the meter. 

In MNM there is only one form of mass as inertial mass = passive gravitational mass = active gravitational mass, signified by the presence of $\rho$ in MNM.  

Today Einstein could have been perfectly happy with MNM as a relativistic universal mechanics with all observers agreeing on the same speed of light according to SI standard.

But that was not the situation in 1905 with physicists struggling to explain the null result of the Michelson-Morley experiment showing a speed of light independent of inertial motion in line with the SI standard, which was not yet made into an agreement and so seemed to require physics beyond NM. 

This is where Einstein stepped in by replacing NM by a new form of relativistic mechanics involving strange new effects of time dilation and space contraction as an explanation of the MM null result based on Lorentz transformation instead of Galilean transformation. Einstein thus dethroned Newton/Galileo to take the top position with SR, which brought him immense fame in a Faustian deal, which he admitted by asking for mercy: Newton, forgive me! 

But replacing NM by SR was a step away from rationality, because agreement/standard was being confused with physical fact and this has been carried into our time: If you ask a physicist of today if the speed of light of $299792458$ meter per second is a matter of definition/standard, you will get the response that it is also a physical fact: It is an agreement about physics, which is also a physical fact. It is like agreeing that 1+1 = 2 as a definition, while insisting that it is also a physical fact which you can subject to experimental verification and possible falsification.

While NM is rational and so understandable, SR is irrational and so not understandable. Modern theoretical physics is based on SR and so has to struggle with irrationality. This is the root cause of the crisis of modern physics: irrationality brought by Einstein.

More aspects of the irrationality of SR is given in Many Minds Relativity including aspects of NM in extreme situations with very large material speeds.  

SR was met by skepticism, which forced Einstein to lift the bet to General Relativity GR based on a postulate of inertial mass = gravitational mass automatically satisfied by NM, thus without substance. This added to Einstein's fame even if no Nobel Prize has been given to SR/GR because the Nobel Committee has remained skeptical for 100 years. 

The two pillars of classical physics are Newton's mechanics and Maxwell's electromagnetics describing the different physics of matter and light. Einstein claimed that Newton's mechanics is wrong, because it does not describe light, which lacked rationality.  

Summary: Modern physics was triggered by the null result of the MM experiment, which appeared to require new physics to explain why all inertial observers agree on the speed of light as a matter of physics. Einstein took on the challenge sitting at his desk as patent clerk performing "thought experiments" in support of SR starting from an assumption that all inertial observers agree on the speed of light thus simply assuming what was to be explained.  

PS: Recall that Einstein based SR on the following two postulates

1. The speed of light is the same for all inertial systems.
2. Physical laws take the same form in all inertial systems.  

We understand that today 1 is an agreement and so not a statement about physics, nor does 2 contain any actual physics. It means that SR, as being based on postulates without real physics, does not say anything about real physics. This is clearly understood by any physicist with classical training in rational thinking, but not by modern physicists confused by irrational thinking.