- Varying Speed of Light (VSL) theory
- Their authors don't understand that one can always change her units. They don't know what's the difference between dimensionless and dimensionful quantities.
- The meter is moreover defined as 1/299,792,458 of a light second, so according to current definitions, a varying speed of light is simply a contradiction.
- One doesn't gain anything whatsoever by redefining the speed of light in a time-dependent fashion because it is just a time-dependent change of units (or coordinates in GR).
- When the speed of light is allowed to be different for various phenomena, we need to determine the right modifications in all equations of physics, including Maxwell's equations and others. No VSL paper is doing anything like that.
- Moreover, one expects to end up with a generic non-relativistic theory with infinitely many parameters. The VSL papers never offer any principle that would replace the broken Lorentz symmetry and determine these parameters. They don't even acknowledge this problem.
Tonight, Magueijo and Moffat have submitted an answer that have made me so upset by its breathtaking stupidity that I simply had to write this text to calm down. ;-) They don't understand a single one among Ellis' obvious complaints. Instead, they paint themselves as new Galileos because they are ready to make a constant variable.
Important physics has never worked like that. Quite on the contrary. Every new major revolution in physics has shown that a certain conversion parameter was not only constant but it was meaningful to set it equal to one.
Joule has figured out that heat and energy can be transformed to each other. We can thus use the same unit for both quantities: to celebrate his discovery, we call the international unit a Joule.
Einstein has found out that space and time are equivalent. This allowed him to declare "c" to be a universal constant. Moreover, all adult physicists who need relativistic phenomena use units where "c=1". This choice also implies that mass and energy are essentially the same thing.
Analogously, quantum physics is closely associated with Planck's constant. Frequencies are the same thing as energies. Adult physicists set "hbar=1". In quantum gravity we may also set Newton's constant "G=1" although in perturbative string theory, it is more natural to set "alpha'=1".
We no longer need degrees to measure angles because rads make equations simpler. Also, we don't need Avogadro's constants and moles because we can count individual atoms and molecules which are better "units" than moles. The number of constants we need to write into our equations decreases.
Making constants variable is going exactly in the opposite direction than what progress in theoretical physics has always been doing. The only "constants" that should be variable are those that depend on some parameters of the environment. But such a declaration of their variability is only interesting once we understand how the environment actually works. Saying that quantities should become variable without understanding how they vary is a meaningless sleight of hand but certainly not a complete theory of anything.
A very similar criticism applies, to a lesser extent, to doubly special relativity etc. The people who work on all these stupid things have a tremendous problem to distinguish physics from conventions, predictions from ways of writing things, deep insights from vacuous sequences of mathematical symbols. They don't understand what a choice of units and field redefinitions means and why they're unphysical. Despite all of their profound ignorance about basics of physics, these crackpots are extremely arrogant (Magueijo is the #1 example, of course) - they view themselves as competitors of inflationary cosmology and many other key segments of science - which makes me quite upset. ;-)
And that's the memo.