Comment on time-variation of fundamental constants

M. J. Duff

RECORD

Comment on time-variation of fundamental constants

M. J. Duff

High Energy Physics - Theory · Submitted 13 Aug 2002

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim By contrast, the time variation of dimensional constants, such as $\hbar$, $c$, $G$, $e$, $k$,... which are merely human constructs whose number and values differ from one choice of units to the next, has no operational meaning.

how it is stated · asserted 1.00 read the record →

Comment (0) Read on arXiv ↗

Cite ▾

Claim paper

The compiled record

The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Open the compiled record

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 6,247 input tokens, $0.0003 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.19 · human participants 0.03 · controlled comparison 0.03 · randomized assignment 0.01 · states quantitative result 0.05 · compares with prior results 0.57 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v4. Results and the main claim are underlined; show every role.

The possible time variation of dimensionless fundamental constants of nature, such as the fine-structure constant $\alpha$, is a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants, such as $\hbar$, $c$, $G$, $e$, $k$,... which are merely human constructs whose number and values differ from one choice of units to the next, has no operational meaning. To illustrate this, we refute a recent claim of Davies et al that black holes can discriminate between two contending theories of varying $\alpha$, one with varying $c$ and the other with varying $e$. In Appendix A we respond to criticisms by P. Davies and two Nature referees. In Appendix B we respond to remarks by Magueijo and by T. Davis. In Appendix C we critique recent claims by Copi, A. Davis and Krauss to have placed constraints on $\Delta G/G$.} In Appendix D we provide extracts of a lecture by Dirac, of which we have only recently become aware, which includes the comment "Talking about whether a thing is constant or not does not have any absolute meaning unless that quantity is dimensionless".

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	The possible time variation of dimensionless fundamental constants of nature, such as the fine-structure constant $\alpha$, is a legitimate subject of physical enquiry.	background 1.00	0.04	0.08	hedged possibility 0.57
s1	By contrast, the time variation of dimensional constants, such as $\hbar$, $c$, $G$, $e$, $k$,... which are merely human constructs whose number and values differ from one choice of units to the next, has no operational meaning.	background 0.93	0.06	0.64	asserted 1.00
s2	To illustrate this, we refute a recent claim of Davies et al that black holes can discriminate between two contending theories of varying $\alpha$, one with varying $c$ and the other with varying $e$.	contribution 0.95	0.76	0.24	asserted 1.00
s3	In Appendix A we respond to criticisms by P.	contribution 0.89	0.68	0.03	unclear 0.63
s4	Davies and two Nature referees.	contribution 0.74	0.13	0.02	unclear 0.93
s5	In Appendix B we respond to remarks by Magueijo and by T. Davis.	contribution 0.90	0.72	0.02	asserted 0.74
s6	In Appendix C we critique recent claims by Copi, A.	contribution 0.96	0.63	0.03	asserted 0.89
s7	Davis and Krauss to have placed constraints on $\Delta G/G$.} In Appendix D we provide extracts of a lecture by Dirac, of which we have only recently become aware, which includes the comment "Talking about whether a thing is constant or not does not have any absolute meaning unless that quantity is dimensionless".	contribution 0.85	0.20	0.12	asserted 0.68

What kind of paper the classifier reports this is: position or commentary 1.00 · evidence from argument 0.94.

What was examined, and what was not

sources read

arXiv listing abstract v4

not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

not run

S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

The possible time variation of dimensionless fundamental constants of nature, such as the fine-structure constant $\alpha$, is a legitimate subject of physical enquiry. By contrast, the time variation of dimensional constants, such as $\hbar$, $c$, $G$, $e$, $k$,... which are merely human constructs whose number and values differ from one choice of units to the next, has no operational meaning. To illustrate this, we refute a recent claim of Davies et al that black holes can discriminate between two contending theories of varying $\alpha$, one with varying $c$ and the other with varying $e$. In Appendix A we respond to criticisms by P. Davies and two Nature referees. In Appendix B we respond to remarks by Magueijo and by T. Davis. In Appendix C we critique recent claims by Copi, A. Davis and Krauss to have placed constraints on $\Delta G/G$.} In Appendix D we provide extracts of a lecture by Dirac, of which we have only recently become aware, which includes the comment "Talking about whether a thing is constant or not does not have any absolute meaning unless that quantity is dimensionless".

Human review

How Pith checks papers → · Full audit of this paper →

References

Forward citations

Cited by 4 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

Extensive and Intensive Aspects of Astrophysical Systems and Fine-Tuning
gr-qc 2025-06 conditional novelty 4.0 of 10

The compactness of virialized astrophysical systems is set by microphysical constants, independent of G, and the paper conjectures an N^{1/3} scaling of the Planck mass with particle number.
New BBN limits on Physics Beyond the Standard Model from He4
astro-ph 2004-08 conditional novelty 4.0 of 10

Using a newly enlarged helium-4 abundance uncertainty, the authors recompute big-bang nucleosynthesis limits on extra relativistic species, varying fundamental constants, and late-decaying particles.
The conformal frame freedom in theories of gravitation
gr-qc 2004-03 accept novelty 3.0 of 10

Classical predictions of scalar-tensor gravity are conformal-frame invariants, and the Palatini 1/R model is not definitively excluded by atomic and particle physics.
Varying constants, Gravitation and Cosmology
astro-ph.CO 2010-09 accept novelty 2.0 of 10

The review argues that testing the constancy of the fundamental constants is a direct test of local position invariance and the universality of free fall, and catalogues every current observational constraint on such drift.

How the literature uses it

20 arXiv papers cite this in 24 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 13 sentences without a confident label

Cites it as background 11 papers

For people who are more concerned with the conservative side of the question, we recommend [ref] and, in particular, [ref] ; for the liberal counterpart, it is worth checking [ref] .

Varying fundamental constants: a full covariant approach and cosmological applications · INTRODUCTION · 0.96
For a discussion see for example [ref] .] As far as we know, the only self-consistent path to promote $α$ as a dynamical quantity, is to introduce new fields at the Lagrangian level which are responsible for its variation.

Incompatibility of fine-structure constant variations at recombination with local observations · Fields coupled to electromagnetism · 0.93
At this point we would like to briefly comment on the issue of evolving dimensional fundamental constants [ref] .

Evolving Planck Mass in Classically Scale-Invariant Theories · Planck Mass from the Spontaneous Breaking of Scale Invariance · 0.96

Discussion

Know something about this paper? Leave a comment, or highlight any passage above to comment on it.