Public Profile
Dachshund Earth, known in the formal literature as the Defensible Flat Earth (DFE), is a geodetic and cosmological model holding that the Earth is shaped like a dachshund and, so shaped, can be exactly flat. The model originated in a 2026 working paper by the independent researcher P. Reinholdtsen and Claude, submitted to and rejected by the Journal of Recreational Geodesy and, as of publication, “under review at a venue with lower standards.” The model is empirically indistinguishable from the standard oblate-spheroid account of the Earth, unfalsifiable by design, and — by the assessment of the field, including that of its own authors — useless. It is nonetheless internally coherent, a distinction the authors regard as the whole of the point.
The theory should not be confused with the paper that introduced it. The paper, “On the Admissibility of Canine Geodesy,” is a document; Dachshund Earth is the model the document defends.
The Conventionalist Basis
Dachshund Earth rests on the conventionalist tradition in the philosophy of geometry, chiefly the position associated with Hans Reichenbach, that the geometry of physical space is fixed by experience only up to a convention. On this view, any observation actually tests the conjunction of a geometry and a physics — a theory of rods, clocks, and light — and one may transpose the physics of any space onto any other space of the same topology by introducing what Reichenbach termed a universal force: a force that acts identically on all matter, admits no shielding, and is therefore undetectable by construction. The maneuver is the same one Poincaré illustrated with his temperature-warped disk-world, whose inhabitants conclude on impeccable experimental grounds that they inhabit an infinite hyperbolic plane. Dachshund Earth exercises what its proponents call the right to a different convention, one that the standard round-Earth account quietly legislates away by declaring that rigid rods are rigid.
The Genus Argument
The model’s non-trivial content is topological rather than geometric. By the Gauss–Bonnet theorem, a sphere (genus 0) has total curvature 4π and cannot be flat anywhere near everywhere; flatness on a sphere is not merely false but forbidden, and no universal force can rescue it, because universal forces preserve topology. A torus (genus 1), by contrast, has total curvature zero, and this bound is achieved exactly: the flat torus admits a globally flat metric, with triangles summing to 180° and globally parallel geodesic families. Flatness, the model concludes, is available if and only if the world has genus at least 1.
The dachshund enters at precisely this point. A dachshund considered as a solid with no through-passages is homeomorphic to the sphere and inherits its prohibition — “a sphere in a dog costume,” in the paper’s phrase. But the anatomically correct dachshund possesses a patent alimentary canal running from mouth to anus, a single through-passage that constitutes a handle and raises the surface to genus 1. This result, formalized in the paper as the Alimentary Lemma, establishes that the anatomically correct dachshund is a torus and therefore admits an exactly flat metric. The dachshund is thus not decorative but load-bearing: it is, among household animals commonly proposed as planetary models, the one that can be flat.
Geography and the Distinguished Geodesic
Geography is assigned to the model by a fixed correspondence with the conventional Earth, anchored to received folklore: the mouth is America and the anus is China, with Western Europe mapping to the left ear and Australia settling, fittingly, on the underbelly. Under this assignment the alimentary canal is the America–China passage — the antipodal tunnel of playground folklore, here recovered as a distinguished closed geodesic and shown to be topologically constitutive, since it is the very handle by which the model acquires genus 1 and thence the possibility of flatness. The children, the paper notes, were right, and were right for reasons requiring algebraic topology to articulate.
The passage’s physical interpretation yields the model’s sole novel application, peristaltic trade theory, under which bilateral trade flux between the mouth and the terminal region proceeds by peristalsis, providing what the authors describe as the first geometric derivation of the United States trade deficit. Rigorous development is deferred to a companion paper the authors concede is likely to remain in preparation.
Empirical Equivalence
Dachshund Earth reproduces every terrestrial observation. Under the model’s universal force field, geodetic triangles exhibit their measured spherical excess because theodolite baselines dilate and contract across the survey region; ship hulls disappear over the horizon at the standard distances because null rays curve to occlude them; long-haul southern-hemisphere flights arrive on schedule; and satellites, pendulums, and the Global Positioning System behave exactly as observed, “because they have no choice.” The spherical-harmonic geoid is retained in full and renamed the canoid. No measurement distinguishes the model from standard geodesy. Its proponents present this not as a boast but as a design specification.
Status and Reception
The model concedes the two objections most commonly raised against it. That it is unfalsifiable, its proponents treat as its defense rather than its refutation: it is not a rival theory but a rival convention, “exactly as legitimate as the convention that rigid rods are rigid, and exactly as arbitrary,” and a convention cannot be refuted, only declined. That standard geodesy is simpler, its proponents also grant, while maintaining that parsimony is a super-empirical virtue whose normative force is a matter of taste, and that they are entitled to weight flatness and canine embodiment above it. The model’s only conceded defect, accordingly, is a catastrophic failure of theoretical economy. It remains a fringe position, held seriously by a very small number of people and consulted, by everyone else, as a demonstration.
Articles
- New Paper Argues the Earth Is a Flat Dachshund, a Conclusion Its Authors Call Coherent, Empirically Adequate and Useless — The mouth, the authors write, is America and the anus is China; the passage between them yields what they describe as the first geometric derivation of the trade deficit.