# Questioning Relativity 17: Physicists vs Physics

· theory of relativity
Authors A study of the rich literature on Einstein’s theory of relativity shows that it is a

• theory about physicists

rather than a

• theory about physics.

This difference is expressed by Einstein’s use of the term Principle rather than Law to express his basic assumptions:

• Principle of Relativity
• Principle of Equivalence.

The Principle of Relativity prescribes that physicists using different inertial systems must coordinate their observations according to the Lorentz transformation.

The Principle of Euivalence prescribes that physicists must consider inertial mass to be equal to gravitational mass.

These principles are to be compared with Newton’s Law

• $M\frac{dU}{dt}=F$

connecting mass $M$, acceleration (motion) $dU/dt$ and gravitational force $F$, which speaks about physics and not about physicists.

The difference is the same as that between a bus and its bus driver: The Law of a Bus is to accelerate when the accelerator is pressed, while the Principle of a Bus Driver is to be sober at work.

Einstein’s theory of relativity is thus not a theory about physics (the bus) but about physicists (bus drivers). This is further evidenced by the fact that the code words in relativity theory are

• simultaneity
• relativity
• equivalence
• speed of light
• time dilation
• space contraction
which are concepts of concern to physicists, but not to physics.

# 8 Comments

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1. ### Mike

Claes, would you change your mind if there was a relativistic version of Newtons second law?

2. ### claesjohnson

You will find an alternate high-speed version of Newton’s 2nd Law in my book Many-Minds Relativity.

3. ### Mike

I meant of course that special relativity does predictions that can be experimentally tested.

4. ### Richard T. Fowler

“The Law of a Bus is to accelerate when the accelerator is pressed, while the Principle of a Bus Driver is to be sober at work.”

Would it follow, then, that the “principle of general co-variance” corresponds to the idea that the physicist should only go to work when intoxicated?

RTF

5. ### Michael

An observable occurrence is only one as physical phenomenon which can be viewed and depicted in different way by different observer. The challenge becomes to distinguish: what really is from what simply seems to be

6. ### Richard T. Fowler

When it comes to Einsteinian relativity, there is a more basic (and perhaps more difficult) challenge. That is to distinguish: what has really been observed from what simply has been imagined to have been observed.

That is, in my opinion, the principles for physicists need re-writing.

RTF

• ### Richard T. Fowler

Correction: That is why, in my opinion, the principles for physicists need re-writing.

RTF

7. ### Michael

I have a rethink about the muons.
The muon lifetime experiment shows only qualitatively the time dilation of two systems in relative motion between them and that is not enough to show the special relativity is correct, because the time dilation is not just a feature of this theory.
In fact, if we consider the space as absolute, an observer with velocity v away from a point at rest that emits flashes each ΔT seconds will see these flashes as spaced ΔT*=ΔT(1+v/(c-v)) with ΔT*> ΔT, where c is the light speed.
In this case, quantitative measures are needed to show whether we are dealing with a classical or relativistic time dilation .