Sabine Hossenfelder

Sabine Hossenfelder
Residence	Germany
Nationality	German
Known for	Lost in Math; criticism of beauty and naturalness as guides to theory; superdeterminism
Scientific career
Fields	Physicist, Philosophy of Science
Institutions	NORDITA; Frankfurt Institute for Advanced Studies; LMU Munich (to 2025)

Sabine Hossenfelder is a German theoretical physicist, author and science communicator who has become the most widely heard critic of the direction of modern theoretical physics — and who is heard from inside it.

That is what makes her unusual, and worth a page here. Hossenfelder is not an outsider. She holds a doctorate in theoretical physics, has published more than fifty peer-reviewed papers, and carries an h-index of about 38 with some 6,750 citations. She does not dispute relativity, does not dispute quantum mechanics, and — unlike much of the literature catalogued on this wiki — holds that dark matter is real. Her quarrel is not with the results of twentieth-century physics but with what the field has been doing since: substituting aesthetic judgement for evidence, defending programmes that decades of experiment have failed to support, and sustaining all of it with an incentive structure she regards as corrupt.

Her verdict on her own discipline, delivered in 2025, was that it is "rotten to the core."

Career

Hossenfelder was born in Frankfurt. She took a diploma in mathematics at Goethe University in 1997 and a doctorate in theoretical physics there in 2003, under Horst Stöcker, on black-hole production in large-extra-dimension models.

She held postdoctoral positions at the GSI Helmholtz Centre, the University of Arizona, the University of California Santa Barbara and the Perimeter Institute, then an assistant professorship at NORDITA in Stockholm from 2009 to 2015. From 2015 to 2023 she was a research fellow at the Frankfurt Institute for Advanced Studies, leading a group on analogue systems for gravity duals, and received the institute's inaugural Award for Innovative Thinking in 2019. She was subsequently at the Munich Center for Mathematical Philosophy at LMU Munich.

In April 2024 she left academic research for full-time work as a science communicator, announcing it in a video titled "My dream died, and now I'm here"; her Munich affiliation ended in 2025. She therefore now writes and speaks from outside the institutions she criticises — a change that her critics and her supporters read very differently.

Research

Her technical work is in quantum gravity phenomenology — the search for observable consequences of quantum gravity, including minimal-length scenarios, on which she wrote a widely cited review in Living Reviews in Relativity in 2013. She has worked on black-hole information with Lee Smolin, and on dark matter.

Two strands are genuinely heterodox by mainstream standards:

Superdeterminism. With Tim Palmer she has argued for reviving superdeterminism as a response to Bell's theorem — the position that the assumption of statistical independence between measurement settings and hidden variables may simply be false, which would allow a locally causal and deterministic account of quantum mechanics. This is a minority view in quantum foundations, and she has defended it against the standard objection that it amounts to a conspiracy of initial conditions.

Superfluid dark matter. She has worked on models in which dark matter behaves as a superfluid whose phonons mediate a MOND-like force within galaxies while behaving as ordinary particle dark matter on cosmological scales — an attempt to take the observational successes of MOND seriously without abandoning dark matter. Characteristically, she has also published constraints against such models, and against a fuzzy dark-matter model, which is worth noting: she is not a partisan of the positions she explores.

The critique of modern physics

Hossenfelder's public argument, developed in Lost in Math (2018) and pressed ever since, has three parts.

Beauty is not evidence. In the absence of new data in the foundations of physics for some forty years, theorists have fallen back on aesthetic criteria — simplicity, elegance, and above all naturalness, the requirement that dimensionless constants be of order one. These criteria are subjective, have no track record of reliability, and have generated supersymmetry, grand unification and the multiverse, none of which experiment has supported.

The incentives entrench the failure. Careers, grants and citations reward producing more papers within an established programme, not abandoning it. A theory that has failed for decades continues to be worked on because working on it is what the funding structure pays for.

The problems being solved are often not problems. She argues that much theoretical work addresses pseudo-problems — questions that feel unsatisfying but signal no actual inconsistency in the theory — and that the proper task is to work on genuine internal contradictions instead.

Her prescriptions follow: name your aesthetic assumptions and test them, work on inconsistencies rather than on ugliness, talk to philosophers of science, and — in her more recent and blunter formulation — stop funding the work that is not producing results.

"I was asked to keep this confidential"

On 15 February 2025 Hossenfelder published a video under that title, in which she read out an email she had received about seven years earlier from a physicist she describes only as someone who "at the time worked at a top institution in the United States." It has been viewed over three million times.

The email is a rebuke. Its author objected to her going public with criticism of the field — she had just published a comment in Nature Physics titled "Science needs reason to be trusted" — and argued that the criticism threatened the livelihoods of thousands of people. In doing so, he conceded the substance of her case:

If you like, yes, what we created is a bubble, but it has helped thousands of those guys and their families not to die from hunger.

— Anonymous correspondent, read by Sabine Hossenfelder (15 February 2025)

The writer identifies himself as an author of a named beyond-the-Standard-Model theory, which he characterises as "pretty useless stuff, old, refurbished with a couple of new bells and whistles. But if people buy this and it helps them to get grants, who cares?" Of the public funding the field: "For people who pay us, all we do is just noise. They have zero idea that elementary particles exist. They pay us from public funds, not from their own." And of the effect on the field's composition: "My heart is bleeding when I regularly see bright, intelligent persons with independent ways of thinking leaving academia or getting kicked out, whereas obedient idiots remain."

He warned her against the fate of Lee Smolin and Peter Woit.

Hossenfelder used the video to argue that current large projects — she names DUNE at Fermilab and the Electron-Ion Collider at Brookhaven rather than any European facility — are justified by pseudo-problems and serve chiefly to keep particle physicists employed, and concluded that "the only way to fix the problem is to stop paying them." She called the field "rotten to the core" and colleagues who stay silent "cowards without a shred of scientific integrity."

Two qualifications belong with this account, and the article would be dishonest without them.

First, Hossenfelder states on camera that she cannot demonstrate the email is genuine: "I can't prove to you that this email is real, so you'll have to take my word for it." The correspondent is unnamed and the identifying details removed at his request. Commenters at the time raised the obvious objection — that a working physicist is unlikely to describe his own research as worthless in writing while asking for confidentiality.

Second, the email is widely described second-hand as coming from an LHC or CERN scientist and as containing the phrase "garbage science". Neither is accurate. The correspondent is a theorist and model-builder, not an experimentalist, and neither CERN nor the LHC is mentioned in the email at all. The phrase "garbage science" is used by nobody; Hossenfelder's own term in the video is "nonsense research", and she explains that she uses it only because the blunter word she prefers is flagged by YouTube. Readers citing this episode should quote what was actually said, which is strong enough without embellishment.

No institutional response from CERN, Fermilab, Brookhaven or any journal has been located.

Public work

Hossenfelder has written the blog Backreaction since 2006, and runs a YouTube channel — formerly titled "Science without the Gobbledygook" — which has grown to around 1.8 million subscribers and over 360 million total views. She has written op-eds for the New York Times and the Guardian, the latter arguing that "the race to invent new particles is pointless."

Reception

Her reception divides sharply, and both sides are worth recording.

Within physics, her diagnosis of the naturalness problem has been taken seriously even by those who reject her conclusions: Frank Wilczek, reviewing Lost in Math in Physics Today, defended symmetry and simplicity as proven heuristics while agreeing with her against post-empirical complacency. The Cambridge philosopher of physics Jeremy Butterfield agreed that narrow programmes have dominated the field, while judging her rejection of supersymmetry and the multiverse too sweeping.

Her critics argue that her claims have escalated beyond what the evidence supports — from particle physics being in trouble, to physics being in trouble, to science itself being in crisis — and that this framing encourages conspiratorial thinking and damages public trust. A 2025 Wall Street Journal piece grouped her with figures it labelled "conspiracy physics", a characterisation that sits awkwardly with her conventional research record.

See also

• Lost in Math
• Philosophy of Science
• Physics
• Alexander Unzicker
• Lee Smolin
• Category: Particle Physics

External links

• Backreaction — her blog, running since 2006.
• YouTube channel — around 1.8 million subscribers.
• Science without the Gobbledygook — her Substack.

Videos cited on this page

• "I was asked to keep this confidential" (15 February 2025) — the anonymous email from a particle theorist, discussed above.
• "My dream died, and now I'm here" (April 2024) — her account of leaving academic research.
• "I can't believe this really happened." (September 2025) — on the end of her university affiliation.