On the detection of absolute velocity in a Newtonian universe

Elias Okon; Jorge Manero; Ricardo Muci\~no

REVIEW 2 major objections 4 minor 12 references

Absolute velocity cannot be shown undetectable from Newtonian dynamics alone.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

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2026-08-01 20:32 UTC pith:B4A5OZD2

load-bearing objection The circularity diagnosis is right and worth engaging; the positive detection scenario has a calibration-access gap that the paper should address. the 2 major comments →

arxiv 2607.16584 v1 pith:B4A5OZD2 submitted 2026-07-18 physics.hist-ph physics.class-ph

On the detection of absolute velocity in a Newtonian universe

Jorge Manero , Ricardo Muci\~no , Elias Okon This is my paper

classification physics.hist-ph physics.class-ph

keywords absolute velocitydetectionmeasurementGalilean invarianceprinciple of relativityabsolute spaceNewtonian mechanicscircular argument

verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

This paper challenges the long-standing claim that absolute velocity would be undetectable in a universe governed by Newtonian mechanics. It argues that every standard proof of undetectability, beginning with the founding argument in classical mechanics, silently assumes that measurement records must be relational or Galilean-invariant—the very point in dispute. Within the theory's own formal resources, the paper shows, absolute and relative velocities behave identically with respect to detection: both allow measurement protocols, correlations, and counterfactuals. So undetectability in a Newtonian universe is an empirical fact about our world, not a consequence of Newtonian dynamics. A sympathetic reader takes away that claims about real-but-undetectable entities within a physical theory require extra, non-dynamical stipulations.

Core claim

The paper's central claim is that no formal argument from Newtonian dynamics shows that absolute velocity is undetectable. The standard route proves that relative quantities are invariant under Galilean boosts, then infers that only such invariant quantities can be detected; that inference, the authors contend, is exactly the claim to be established. They propose a minimal notion of detection: device M detects a property of system S if, through an interaction, some objective physical property of S becomes correlated with some objective physical property of M. Since absolute velocity is objective and physical, and since a purely relational interaction can leave the final absolute velocity of

What carries the argument

The load-bearing device is the collision-detection model: a measuring apparatus M with known initial absolute velocity interacts with a system S through a purely relational (relative-position/relative-velocity-dependent) force. In the one-dimensional elastic case, M's final absolute velocity is v_f^M = ((m_M - m_S)/(m_M + m_S)) v_i^M + (2 m_S/(m_M + m_S)) v_i^S (Eq. 3), so for fixed v_i^M the final velocity encodes v_i^S. This shows that absolute properties can be correlated through relational interactions, even though the center-of-mass absolute velocity decouples from relational degrees of freedom. The second supporting element is the principle that, absent a formal restriction or external

Load-bearing premise

The conclusion rests on the paper's definition of detection as a correlation between any objective physical property of the target and any objective physical property of the measuring device; if detection is instead required to be recorded in invariant or publicly communicable properties, undetectability returns.

What would settle it

A single derivation from Newtonian dynamics alone—using no stipulation about what qualifies as a record—that no correlation can encode a non-invariant property would falsify the paper's claim. Concretely: if one proves that any measurement record must be invariant under Galilean boosts (e.g., by showing the dynamics forces record variables to be invariant), then the elastic-collision encoding of absolute velocity is disallowed and the paper's conclusion fails.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

The undetectability of absolute velocity is demoted from a theorem of Newtonian mechanics to an empirical fact about our universe; a hypothetical Newtonian universe could in principle contain devices that measure absolute velocity.
Formal symmetry-invariance by itself does not decide observability, so standard appeals to the principle of relativity cannot be used to establish what is detectable within a theory.
Claims of 'real but undetectable' entities within a physical theory require explicit, justified stipulations about what counts as a record; such stipulations cannot be smuggled in as consequences of the dynamics.
The paper's elastic-collision scheme provides a concrete, testable protocol for recording absolute velocity in a toy Newtonian world, suitable for simulation or armchair experimentation.
If correct, the distinction between empirical facts and theoretical results sharpens: our observed inability to detect absolute velocity says something about our world, not about Newtonian dynamics.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

The same circularity critique may apply to any theory that declares quantities real but unobservable solely because a symmetry leaves them unconstrained by the theory's own observables—for example, global phases in gauge theories or absolute orientation in relational mechanics.
If any objective property can serve as a record, then 'detectable' becomes relative to the choice of allowed record variables; a testable philosophical thesis follows: every real degree of freedom in a classical theory is detectable in some model unless the theory itself forbids the correlation.
The one-dimensional collision scheme can be generalized to three dimensions and to non-relational forces, mapping precisely which absolute quantities become recordable and under what dynamics.
The paper's argument suggests a reversal of evidential direction: rather than deriving undetectability from symmetry, one could treat the absence of detected absolute velocity in our world as evidence that our universe is not Newtonian—not as evidence that Newtonian dynamics hides absolute velocity.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Desk Editor's Note

The circularity diagnosis is right and worth engaging; the positive detection scenario has a calibration-access gap that the paper should address.

read the letter

Short version: this is a real contribution, not a stalking horse. It shows that Newton's own argument, plus Roberts and Wallace, all rely on an extra premise about which quantities can serve as measurement records, and that premise is not a theorem of Newtonian dynamics. The diagnosis is quotation-grounded and, on the Roberts case, I think it is right. Wallace does indeed stipulate that readout quantities must be independent of the symmetry parameter, and the paper is fair to say that stipulation is doing all the work.

The new things are the all-worlds framing, the explicit treatment of Newton's Scholium, and the elastic-collision correlation in Eq. (3). That equation is correct, and it makes the point that relational interactions can correlate absolute velocities of M and S. Credit where due: this is a clean, non-circular demonstration that the dynamics does not block such correlations.

The soft spot is exactly the one flagged in the stress test. Eq. (3) is a measurement only if v_i^M is known and fixed. In a Newtonian universe with purely relational forces, the absolute velocity of the M+S center of mass is conserved and completely decoupled from every relational variable. So an agent inside the universe cannot learn v_i^M from any relational data; knowing it presupposes the very access at issue. The paper treats the record restriction as the only contested premise, but this is a second, separate stipulation about calibration access. It does not collapse the negative claim—the circularity of the undetectability arguments does not depend on Eq. (3)—but it makes "no formal reasons" sound stronger than the construction supports. If I were the editor, I would ask the authors to state clearly that the correlation is a formal possibility available from a God's-eye point of view, and that the question of internal measurability remains open.

The paper is carefully hedged about not claiming actual detectability, and the broader-consequences section is more speculative but clearly marked as such. The citation pattern is appropriate.

Bottom line: give it to a referee. The central diagnosis is defensible and interesting; the Eq. (3) scenario needs to be sharpened, but that is a revision, not a desk reject.

Referee Report

2 major / 4 minor

Summary. The paper argues that standard arguments for the undetectability of absolute velocity in a Newtonian universe—those of Newton, Roberts, and Wallace—are circular because they assume that only Galilean-invariant quantities can serve as measurement records. The authors propose a broader notion of detection according to which any objective property, including absolute velocity, can in principle encode a measurement. Using an elastic-collision example (Eq. 3), they claim to show that the final absolute velocity of a measuring device can correlate with, and hence record, the initial absolute velocity of a target system. They conclude that undetectability of absolute velocity is an empirical fact about the actual world, not a theorem of Newtonian dynamics.

Significance. If correct, the paper would shift the debate: the relativity principle would not by itself rule out the possibility of detecting absolute velocity; it would be a contingent feature. The paper's strengths are its clear identification of the bridging premise in the standard arguments, its explicit engagement with recent literature (Roberts 2008, Wallace 2022, Middleton and Murgueitio Ramírez 2021), and its concrete dynamical model showing that relational interactions can produce correlations between absolute velocities. The paper is also appropriately modest in declining to claim that absolute velocity is detectable—only that the usual formal case for undetectability fails. However, as detailed below, the positive protocol in §5 relies on a knowledge assumption that is not addressed, and the permissive detection criterion in §3 is stipulated rather than argued.

major comments (2)

[§5, Eq. (3) and §7] The claim that v_f^M 'conveys full information' of v_i^S for a 'known, fixed' v_i^M is not a measurement protocol available from within the Newtonian universe. With only relative forces, the center-of-mass velocity of M+S is dynamically decoupled from all relational degrees of freedom, so no sequence of relational observations can determine v_i^M; a global Galilean boost changes v_i^M and v_f^M while leaving every relational record invariant. Thus an internal observer cannot know or fix v_i^M without already having access to absolute velocity—the very access at issue. If v_i^M is instead treated as an external boundary condition, Eq. (3) describes an external observer's bookkeeping, not a detection performed inside the world. Since §7 explicitly asserts that 'the initial absolute velocity of a system S can be reliably recorded in the final absolute velocity of a measuring device M,' this
[§3 and §4] The paper's case against Roberts and Wallace depends on the principle that 'in principle, all objective, physical properties of a system could participate in the encoding of a measurement.' This principle is asserted, not derived. Roberts and Wallace impose the invariant-record condition precisely because they take public communicability and reproducibility to be constitutive of measurement; the paper dismisses these as 'stipulations' or 'empirical features of our world,' but does not give a substantive argument that a mere correlation between two absolute velocities counts as a detection. The disagreement is therefore not that the standard authors are committing a formal fallacy; it is a substantive dispute over the concept of measurement. The paper needs to justify its broad criterion against the communicability/reproducibility arguments, otherwise the conclusion 'there are no formal r

minor comments (4)

[§5, first paragraph] Typo: 'undectability' should be 'undetectability.'
[References] The Newton reference gives 'Florian Cajoli'; the correct name is 'Florian Cajori.'
[§2] The attribution of the Galilean boost statement to Newton's Corollary V is fine, but the modern concept of a Galilean transformation is not exactly Newton's; a brief clarification would help readers.
[§4] The treatment of Wallace (2022) is somewhat compressed; providing page numbers for the quoted passages would aid verification.

Circularity Check

1 steps flagged

Positive detection protocol in Eq. (3) presupposes a known absolute initial velocity v^i_M, so the paper's claim of formal parity between absolute and relative velocities assumes the very access at issue.

specific steps

self definitional [Section 5, Eq. (3) (one-dimensional elastic collision example)]
"Then, for a known, fixed v^i_M, v^f_M conveys full information of v^i_S—i.e., M measures the initial velocity of S, encoding it in v^f_M."

v^i_M is itself an absolute velocity. In the stipulated Newtonian universe all forces depend only on relative quantities (§2), so the absolute velocity of the center of mass is conserved and decoupled from every relational variable; no finite relational observation can determine, prepare, or fix v^i_M. Knowing/fixing it is exactly the capability at issue. Thus Eq. (3) is not an internal measurement protocol: the quantity it treats as a known calibration input is the same kind of quantity it claims to measure. If v^i_M is instead supplied as an external boundary condition, the correlation is available only to an observer who already possesses absolute-velocity information. Either way, the construction assumes, rather than establishes, epistemic access to absolute velocity—the same question-

full rationale

The paper's main negative thesis—that Newton's, Roberts's, and Wallace's undetectability arguments depend on an extra stipulation that records must be Galilean-invariant—is not itself circular; it is a legitimate burden-shifting critique. The question-begging step is in the positive construction that is supposed to show that absolute and relative velocities have identical formal detection features. Eq. (3) obtains v^i_S from v^f_M only for a 'known, fixed' v^i_M; but v^i_M is an absolute velocity, and in the Newtonian universe under discussion the absolute velocity of the center of mass decouples completely from all relative variables, so no internal relational measurement can supply it. The protocol therefore takes as an input the very sort of information it is meant to produce, and reading the record v^f_M has the same structure. The paper's §3 principle that 'all objective, physical properties' can encode measurements is stipulated rather than derived; while the paper uses it dialectically to expose a similar stipulation on the other side, it cannot by itself establish that absolute velocity is detectable from within the world. The self-citation to Manero et al. (2025) is only an analogy and is not load-bearing. No further circular steps were found.

Axiom & Free-Parameter Ledger

0 free parameters · 5 axioms · 0 invented entities

Conceptual paper: no fitted numbers and no invented entities. The ledger isolates the premises the argument needs: a correlation-sufficiency analysis of detection, the exclusion of actual-world empirical data, the in-principle recordability of any objective property, and the presupposed known v^i_M in the collision protocol.

axioms (5)

domain assumption A device detects a feature of a system iff their interaction produces a lawful correlation between some objective property of the system and some objective property of the device; correlation suffices for detection.
§3: 'it is said that device M detects or measures some features of system S when, in virtue of a mutual interaction, certain properties of S wind up correlated with certain properties of M.' The paper's negative conclusion holds only if records need not satisfy additional constraints (invariance, publicity, regress-terminating perceptibility).
domain assumption Empirical facts about our actual universe must be excluded from the analysis of the hypothetical Newtonian universe.
§2/§7: 'one should be very careful not to employ any actual empirical data, as this pertains to our universe, not the hypothetical one.' Used to dismiss Roberts's 'form of life'/communicability argument.
domain assumption In principle, all objective physical properties of a system could participate in encoding a measurement result.
§3: 'unless there is a formal restriction within a theory or an external stipulation to the contrary, all objective, physical properties could, in principle, be involved in the representation of a result.' Load-bearing for converting correlations into detection.
ad hoc to paper The elastic-collision protocol presupposes the detector's own initial absolute velocity v^i_M is known.
§5, Eq. (3): v^f_M is read as carrying full information of v^i_S 'for a known, fixed v^i_M'; obtaining v^i_M requires prior absolute-velocity knowledge, a regress the paper does not address.
domain assumption Grant the standard-argument assumption that all forces depend only on relative quantities; the paper argues the undetectability conclusion still fails.
§2: 'the point we want to make is that, even if, by stipulation, all forces only depend on relative quantities, it still does not follow that absolute velocities are undetectable.'

pith-pipeline@v1.3.0-alltime-deepseek · 8657 in / 20360 out tokens · 213311 ms · 2026-08-01T20:32:20.223102+00:00 · methodology

0 comments

read the original abstract

As a fundamental arena for the development of his dynamics, Newton postulated the existence of absolute space, in which bodies innately possess absolute velocity. Despite this, Newton argued that, although real, absolute properties cannot be detected. Since then, the claim that absolute velocity would be undetectable in such a Newtonian universe has been generally accepted. Here, we show that standard arguments for such a claim, beginning with the one offered by Newton himself, beg the question. We conclude that there are no formal reasons to believe that absolute velocity would be undetectable in a Newtonian universe.

discussion (0)

Reference graph

Works this paper leans on

12 extracted references · 1 linked inside Pith

[1]

Brown, H. R. (2005). Physical Relativity . Oxford University Press

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[2]

Dasgupta, S. (2016). Symmetry as an E pistemic N otion ( T wice O ver). The British Journal for the Philosophy of Science , 67(3):837--878

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[3]

Dürr, D., Goldstein, S., and Zanghí, N. (1992). Quantum equilibrium and the origin of absolute uncertainty. J. Stat. Phys. , 67:843--907

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[4]

Heisenberg, W. (1971). Physics and Beyond: Encounters and Conversations . Harper Torchbooks. Harper & Row

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Jacobs, C. (2022). Absolute velocities are unmeasurable: R esponse to M iddleton and M urgueitio R amirez. Australasian Journal of Philosophy , 100(1):202--206

2022
[6]

Luc, J. (2024). The unmeasurability of absolute velocities from the point of view of epistemological internalism. Erkenntnis , 89(8):3309--3327

2024
[7]

Manero, J., Muciño, R., and Okon, E. (2025). Exposing an unjustified assumption in the P ilot-wave derivation of absolute uncertainty. arXiv:2508.06667

Pith/arXiv arXiv 2025
[8]

and Murgueitio Ram \' rez, S

Middleton, B. and Murgueitio Ram \' rez, S. (2021). Measuring absolute velocity. Australasian Journal of Philosophy , 99(4):806--816

2021
[9]

Murgueitio Ram \' rez, S. (2024). Symmetries and M easurements. Philosophy Compass , 19(6):e13006

2024
[10]

Newton, I. (1934). Principia , volume 1. University of California Press. trans. by A ndrew M otte, rev. by F lorian C ajoli

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[11]

Roberts, J. T. (2008). A P uzzle about L aws, S ymmetries and M easurability. The British Journal for the Philosophy of Science , 58:143--168

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[12]

Wallace, D. (2022). Observability, R edundancy, and M odality for D ynamical S ymmetry T ransformations. In Read, J. and Teh, N. J., editors, The Philosophy and Physics of Noether’s Theorems: A Centenary Volume , page 322–353. Cambridge University Press

2022

[1] [1]

Brown, H. R. (2005). Physical Relativity . Oxford University Press

2005

[2] [2]

Dasgupta, S. (2016). Symmetry as an E pistemic N otion ( T wice O ver). The British Journal for the Philosophy of Science , 67(3):837--878

2016

[3] [3]

Dürr, D., Goldstein, S., and Zanghí, N. (1992). Quantum equilibrium and the origin of absolute uncertainty. J. Stat. Phys. , 67:843--907

1992

[4] [4]

Heisenberg, W. (1971). Physics and Beyond: Encounters and Conversations . Harper Torchbooks. Harper & Row

1971

[5] [5]

Jacobs, C. (2022). Absolute velocities are unmeasurable: R esponse to M iddleton and M urgueitio R amirez. Australasian Journal of Philosophy , 100(1):202--206

2022

[6] [6]

Luc, J. (2024). The unmeasurability of absolute velocities from the point of view of epistemological internalism. Erkenntnis , 89(8):3309--3327

2024

[7] [7]

Manero, J., Muciño, R., and Okon, E. (2025). Exposing an unjustified assumption in the P ilot-wave derivation of absolute uncertainty. arXiv:2508.06667

Pith/arXiv arXiv 2025

[8] [8]

and Murgueitio Ram \' rez, S

Middleton, B. and Murgueitio Ram \' rez, S. (2021). Measuring absolute velocity. Australasian Journal of Philosophy , 99(4):806--816

2021

[9] [9]

Murgueitio Ram \' rez, S. (2024). Symmetries and M easurements. Philosophy Compass , 19(6):e13006

2024

[10] [10]

Newton, I. (1934). Principia , volume 1. University of California Press. trans. by A ndrew M otte, rev. by F lorian C ajoli

1934

[11] [11]

Roberts, J. T. (2008). A P uzzle about L aws, S ymmetries and M easurability. The British Journal for the Philosophy of Science , 58:143--168

2008

[12] [12]

Wallace, D. (2022). Observability, R edundancy, and M odality for D ynamical S ymmetry T ransformations. In Read, J. and Teh, N. J., editors, The Philosophy and Physics of Noether’s Theorems: A Centenary Volume , page 322–353. Cambridge University Press

2022