Measurement Theory and Relativity (Introductory words from my talk)

• I have been studying the early figures that had thought deeply about dimensional analysis such as
Percy Bridgman, Norman Campbell, Frederick W. Lanchester, Alfred O’Rahilly, Herbert Dingle, Julio
Palacios, Louis Essen “The Father of Atomic Time” as well as some more minor figures. One thing
seems a common trait, they all had something to say about Einstein’s Theory of Relativity: all apart
from Lanchester were critical of the theory to some degree, with O’Rahilly, Dingle and Palacios
being by far the most critical. Bridgman thought it essentially correct, and the problem was
presentational. Norman Campbell tried hard to suppress his disdain for Special Relativity,
nevertheless providing material in his book on “Modern Electrical Theory”, together with its
Supplementary Chapters, for students to learn the practical applications of the subject.

• Lanchester had visited the home of Carl Runge in Göttingen, and personally met Minkowski
around 1908, which probably accounts to some extent for his later enthusiasm for Minkowski
Space‐time diagrams greater than any engineer before or since I believe. (See the Preface to
Lanchester’s 1935 book “Relativity” and the Minkowski diagrams in the rest of the book.).

• The reason I think that underlies this critical trend is the fact the paradigm of thought that requires
taking dimension homogeneity seriously as a concept does, not fit easily with the Special Theory of
Relativity and this has prevented some workers from generalising the methods of dimensional
analysis to encompass the theories of relativity in the way they wanted or thought most natural.
This was particularly true of Julio Palacios who thought that dimensional analysis was incompatible
with the Special Theory of Relativity. Another philosopher, Lancelot Law Whyte made a similar
point, in his own way, in his 1931 book “Critique of Physics”.

Measurement Theory and Relativity (Introductory words from my talk)

• I have been studying the early figures that had thought deeply about dimensional analysis such as
Percy Bridgman, Norman Campbell, Frederick W. Lanchester, Alfred O’Rahilly, Herbert Dingle, Julio
Palacios, Louis Essen “The Father of Atomic Time” as well as some more minor figures. One thing
seems a common trait, they all had something to say about Einstein’s Theory of Relativity: all apart
from Lanchester were critical of the theory to some degree, with O’Rahilly, Dingle and Palacios
being by far the most critical. Bridgman thought it essentially correct, and the problem was
presentational. Norman Campbell tried hard to suppress his disdain for Special Relativity,
nevertheless providing material in his book on “Modern Electrical Theory”, together with its
Supplementary Chapters, for students to learn the practical applications of the subject.

• Lanchester had visited the home of Carl Runge in Göttingen, and personally met Minkowski
around 1908, which probably accounts to some extent for his later enthusiasm for Minkowski
Space‐time diagrams greater than any engineer before or since I believe. (See the Preface to
Lanchester’s 1935 book “Relativity” and the Minkowski diagrams in the rest of the book.).

• The reason I think that underlies this critical trend is the fact the paradigm of thought that requires
taking dimension homogeneity seriously as a concept does, not fit easily with the Special Theory of
Relativity and this has prevented some workers from generalising the methods of dimensional
analysis to encompass the theories of relativity in the way they wanted or thought most natural.
This was particularly true of Julio Palacios who thought that dimensional analysis was incompatible
with the Special Theory of Relativity. Another philosopher, Lancelot Law Whyte made a similar
point, in his own way, in his 1931 book “Critique of Physics”.

That's looking uncomfortably long as well, and to me at least does not really explain your position or the origin of your apparent difficulty with SR, or indeed GR, with which I presume you will also have similar issues?

Here is my own position.

Why should I care what a string of dead folk used to think or who visited whom and when ? I successfully design electronics now that simply would not work if GR and QM were not models for describing the universe that were valid to the degree that allows us to use those models for design purposes. (So, in short, these models work and in that sense as a mathematical abstraction of a world view they are valid.) And then, what else is a model for ?

Minowski diagrams are nice for teaching about past and future cones in a pictorial manner but are nothing very special

(You need GR to correctly predict satellite comms doppler and periodic frequency  effects, and it does, to within the limit of possible accuracy measurements, and you need the QM for the  quasi 2-d 'gas' models of the high frequency transistors that receive the signals with noise figures below the thermal floor, and again the match between model and theory is good.)

While the papers of a hundred years ago discussed the Michelson & Morley experiments and M-Z interferometry in terms of Ether drag, that was set by the limit of their experiments. If they could have measured atmospheric muon density, or flown ceasium clocks around the planet, I'm sure they would have done so.  We are tied by a short lease to the observable facts - the rest is so much fantasy, or more kindly, conjecture.

Now the first day a physical effect comes along we cannot explain with current models, we will need to extend or rewrite the models (laws if you like) in a way that does, as well as covering all the previous observable effects as well.

That will be progress.

Mike.

The talk is not meant for someone already happily indoctrinated with, and accepting of, the instrumentalist philosophy of physics. I am trying to encourage young students to start questioning differing physical and philosophical viewpoints before they are fully processed through the academic system. 

When I first was taught Mechanical Engineering at Manchester University I was expected to be a realist. When I swapped over to physics I was expected to be a realist for things that made sense and an unquestioning instrumentalist for things that didn't make any sense to me. In the late eighties the teaching of the "Shut up and Calculate" anti-philosophy was still at its peak.

Philosophy is interesting to me, even if it is not interesting to most, because I have had to suffer from its vagaries more that most. I am the sort of unreasonable person who dreams of a unitary model to fill my brain with, as Newton and Faraday once did. 

Einstein was a was very much a positivist when he wrote "On the electrodynamics of moving bodies" in 1905. I am trying to help uncover what this means for us today in terms of theory making, understanding of those theories and the subsequent passing on of knowledge to the next generation.

I am presenting Dimensional Analysis/Measurement Theory from very much a realist position to see how it can explain the widespread misunderstanding/misinterpretation of Einstein's two postulates of Special Relativity.

By the way why do you not care who Louis Essen was and what he believed for example, when so much in experimental relativity and the setting up of accurate systems of units (e.g. SI units) depends on him having lived.