"Physics is moving again, and philosophy wants back in"

Albert Wenger is not a physicist. He is a venture capitalist — one of the founders of Union Square Ventures, an early backer of Twitter, Tumblr, and a long list of companies that shaped the internet. So it is worth paying attention when he argues, as he did this week in resuming his long-running "Philosophy Mondays" series, that fundamental physics is finally moving again after decades of frustrated stasis. It is a claim that matters far beyond the seminar room, because how physics moves has a way of moving everything else with it.

Wenger's framing is built around two failure modes, and the clarity of the frame is most of the value. On one side sits what he calls extreme reductionism: the belief that a "theory of everything" in physics would make philosophy unnecessary, because once you have the bottom-level laws, everything above them is just detail. The problem, he argues, is that this dramatically underestimates emergent phenomena — most importantly the growth of information and intelligence, which no bottom-level equation obviously explains. On the other side sits the opposite error, the idea that philosophy can proceed in a clean room of language and logic without ever consulting physics. Both errors, he notes, run into the same wall: we are beings with a physical body, living in a physical world.

The hinge concept Wenger borrows is the absorbing state. A physical system can reach a configuration from which it cannot return — a candle burned to the wick, a star collapsed past the point of return, a human being dead. This matters enormously for philosophy because we cannot simply "reboot." Our moral reasoning is not a thought experiment run on an infinite substrate; it is conducted by creatures who can be permanently removed from the game by physics. Any ethics that forgets this, that treats minds as if they were immortal software, is quietly smuggling in a false premise.

The post's two most striking examples both come from thinkers working the seam between physics and life. Jenann Ismael, whose book How Physics Makes Us Free argues that information and the agents who act on it must be first-class concepts, not afterthoughts. And Sara Imari Walker, whose observation about the search for alien life is the kind of thing that stays with you: many different processes can produce a "biosignature" like gases in an atmosphere, so a signature is never proof — but if you observed satellites being launched into orbit around another planet, you would have affirmative, unambiguous evidence of intelligence. The distinction between a signal that could mean something and a signal that could only mean one thing is exactly the discipline physics has always demanded.

Here is where Wenger turns from framing to news, and the news is genuinely encouraging. For decades the dominant paradigms in fundamental physics — string theory, dark matter, dark energy — have been stuck in place, producing elegant mathematics but a frustrating shortage of testable predictions. What has changed, he argues, is a new willingness to entertain alternative proposals. He points to a conversation with the physicist Philip Mannheim, who offers a lucid case that Einstein's general relativity may simply be missing some higher-order terms — meaning the "missing mass" and "accelerating expansion" we attribute to dark matter and dark energy might instead be a correction to gravity itself.

This is the single most interesting idea in the post, and it deserves more than Wenger gives it, so I want to spend a moment on it. There is a famous precedent for exactly this maneuver in the history of science: the epicycle. For centuries astronomers preserved the geocentric model by layering circles upon circles — epicycles — onto the motions of the planets, each new discrepancy patched with another epicycle, until the whole apparatus became baroque and the Copernican simplification swept it away. The charge that dark matter and dark energy are modern epicycles is not a fringe insult; it is a precise, falsifiable claim about what kind of theory we are dealing with. If a small number of free parameters — or better, a modification of gravity — can account for the same observations without an invisible substance no experiment has ever directly detected, then simplicity itself becomes evidence, in the spirit of Thomas Kuhn's observation that science advances not by accumulating answers but by replacing one framework with another.

And there is a genuinely new empirical wrinkle that makes this more than philosophy. Wenger points to fresh observational data suggesting that astronomers may have been undercounting matter all along — including new work discussed by the physicist Sabine Hossenfelder. If the ordinary matter in the universe turns out to be more plentiful than our telescopes have been telling us, the need to posit a vast reservoir of invisible dark matter shrinks accordingly. Theory pluralism is easy to shrug off; the combination of theory pluralism and a corrected measurement is how paradigms actually fall.

What I find most worth underlining, beyond Wenger's own argument, is the timing. It is rare for three enabling forces to converge at once, and all three seem to be present now. First, the theoretical alternatives — modified gravity, alternative formalizations of quantum mechanics, new ways of reconciling quantum theory with general relativity — have matured enough to be taken seriously rather than dismissed out of hand. Second, new instruments are delivering the kind of data that can arbitrate between them. Third, and this is the piece Wenger gestures at but does not develop, the rapid advance of AI gives physics something it has never had at scale: a tireless hypothesis engine capable of searching the enormous space of possible formalisms. AI will not replace theoretical physicists, but it can dramatically widen the funnel of ideas worth a human's time.

That third point deserves one concrete example to keep it honest. Already, machine-learning methods have been used to rediscover physical laws from raw data — a technique known as symbolic regression, which produced an accurate equation of motion for a double pendulum from measurements alone, without being told Newton's laws. Scale that idea from a lab bench to the frontiers of cosmology and you begin to see why Wenger's optimism is not merely temperamental. The bottleneck in physics was never the equations; it was the search.

Which brings us back to the title's second half. Wenger's deeper project, running through the whole "Philosophy Mondays" series, is to reconnect physics and philosophy after a century of mutual estrangement — physics having retreated into mathematics, philosophy into language. If the hard problems in physics begin to yield, the payoff is not just better equations. It is a restored picture of ourselves as physical beings whose freedom, agency, and morality are real features of a physical world rather than embarrassments to be explained away. That is a claim about the nature of a person, not a claim about the nature of a proton, and it is exactly the kind of question the two disciplines once shared. It is good to see someone try to give it back to them.

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Further reading

• Albert Wenger's original post: Philosophy Mondays: Progress in Physics
• Jenann Ismael, How Physics Makes Us Free (Oxford University Press) — publisher page
• Sara Imari Walker, Life as No One Knows It: The Physics of Life's Emergence (Riverhead Books, 2024)
• Sabine Hossenfelder's YouTube channel, where she discusses the new matter-counting data
• Curt Jaimungal's Theories of Everything podcast, host of the Mannheim and Ismael conversations Wenger cites