Change One Law of Physics and Every Wish Backfires
A live thought experiment from Dragon Con: change just one law of physics to make science fiction real, and every wish gets taken apart for the consequences nobody counted — antigravity equals free energy, hyperspace travel equals handing the technology to every alien civilization.
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The argument · tap a timestamp to hear it
Changing a law of physics changes it for the whole universe
The rule is hard: pick only one, and it has to be practical and feasible within the laws of physics — no perpetual-motion-style having it both ways. Steven starts by handing most science-fiction premises a death sentence — warp drive, shields, phasers, artificial gravity, antigravity — either they violate physics or they fall under non-trivial: theoretically maybe possible, but never going to happen. The real fun of the whole discussion isn't in what you pick, it's in finding the consequences inside each wish that nobody counted.
— Steven NovellaAntigravity means free energy thrown in
Jay wants antigravity, on the grounds that transportation, construction and materials handling would all change. Bob points out it's a twofer: if you could feasibly turn gravity off, you'd turn it on while the water wheel goes down and off while you haul it back up, and you'd have a perpetual motion machine. Steven, as the buzzkill, patches it by force: the energy it costs to turn gravity off has to equal the energy you get out of it — no free lunch. The argument also incidentally kills science-fiction movies — single-stage-to-orbit is simply impossible in a 1g gravity well, and every shot of a ship reaching orbit in a minute is lying, because it assumes antigravity exists.
— Jay NovellaHyperspace travel hands the technology to every alien civilization
Bob picks entering subspace/hyperspace: run ordinary engines over there, come out having crossed a far greater distance — essentially practical FTL. He argues there's no downside risk, because hyperspace is separate from real space and doesn't affect our universe. Steven and Jay immediately push back: changing a law of physics changes it for the whole universe, not just for you, and hostile civilizations could use it to colonize Earth just as well. Bob's answer is to hide — human radio signals dilute into noise a few light-years out, so in principle nobody could work backward to the conclusion that Earth has life. Jay offers a compromise, jump gates: both ends have to be built, so expansion can only be slow, and not every alien comes knocking.
— Bob NovellaZero-point energy is too thin, and forcing it triggers a big rip
Steven's second choice is free energy, specifically zero-point energy. Bob gives the objection: zero-point energy is observationally extremely thin, and lighting a single bulb might take several cubic light-years of space; and if you really injected that much energy into space, cosmic expansion would run away into a big rip that destroys all life. Steven's response is that this is exactly why these aren't laws of physics — every wish, once it actually lands, brings catastrophic consequences, so the fun of the thought experiment is finding the loophole that dismantles the wish. Julia adds her astrophysics-major perspective: if gravity had a knob, 90% of the observations used to infer stellar phenomena from gravity would all be wrecked.
— Bob NovellaEven a bucket of water can compute like a neural network
The core of physical reservoir computing: any nonlinear system — a bucket of swirling water, time-varying mayonnaise — as long as you measure the right spot, its nonlinear interactions can be mapped onto an artificial neural network and made to ‘think’ for you. Someone gave a talk saying, ‘We got mayonnaise to think very slowly.’ Once that analogy holds, scale becomes a variable: if you had a nonlinear system the size of a nebula, you feed it input and measure output at the right point, and it can do the computation for you. The speaker himself admits this is a ‘wild idea’, but stresses that once you shrink physical constants down to something tiny, a pile of strange corollaries pops out.
Roman is a thousand times faster than Hubble, but cast as a supporting player
The Nancy Grace Roman Space Telescope is a wide-field infrared telescope with a 3.4-meter primary mirror, the same size as Hubble, but its design goal isn't ‘better than existing telescopes’ — it's complementary: James Webb excels at deep space, Hubble at staring at specific objects, Roman at taking in a huge swath of sky at once. It can survey a thousand times faster than Hubble, covering in its five-year mission the sky area Hubble would take a thousand years to cover. Once it finds something interesting, you turn Webb and Hubble onto it for a closer look. It will also build a three-dimensional map of the universe and carries a coronagraph to block starlight glare and directly image exoplanets — able to find smaller planets farther from their host stars, correcting the transit method's and radial velocity method's bias toward ‘hot Jupiters’.
A robot baby kicks its legs and kicks up explore versus exploit
The University of Hamburg and Czech Technical University did a ‘robot in a crib’: a baby robot, iCub, placed in a crib with a mobile hanging overhead carrying QR codes, one leg tied to it by a string, and their own deep learning algorithm run to predict the mobile's motion. The result was that the algorithm spontaneously produced the explore versus exploit trade-off — both curious exploration and exploitation of the causality already learned. The researchers treat it as a platform: you can't change a baby's learning algorithm, but you can swap algorithms in a robot, so you can test different versions of contingent learning theory. By contrast, the mainstream of current robot control is deep reinforcement learning: put thousands of copies of the robot in simulation, train with a reward function, then transfer once to the real machine — that's ‘do this and something good happens’, not ‘this causes that’.
The Chinese space station redid the Leaning Tower experiment with rubidium atoms
On the Chinese space station, researchers redid Galileo's falling-body experiment with two clouds of rubidium atoms of different isotopes, one heavier than the other. The free-fall time was about 10 to 12 seconds, far longer than ground experiments, and averaged over many repetitions, the result was that the two clouds fell at rates identical to five parts in ten million. What this verifies is that gravitational mass and inertial mass are exactly the same — in Newtonian mechanics mass shows up in two ways, and in free fall the two effects cancel precisely. What Einstein asked was precisely: why must they be the same? There's no reason they must be. From that comes his thought experiment: in free fall gravity seems to vanish and you're in an inertial reference frame; and in an accelerating elevator light bends, so if gravity and acceleration are equivalent, gravity should bend light too.
In their own words · checked verbatim
Well, Jay gets a good twofer on this one because what you got the ability to turn off gravity in a feasible way, you got like free energy, too
Steven Novella8:08
The best we could hope for is a fraction of the speed of light. 60 70 80% potentially which would be nice.
Bob Novella10:08
There's no way I would you would want to live in a universe where you could travel to the past and actually change your present.
Steven Novella16:10
the end result would be universe expansion so nasty that it could cause the big rip, which we know is scare scary and it just basically destroy all of life
Bob Novella24:16
so in a weird way you can get a bucket of water to think compute
that anything could include consciousness if it's big enough and might maybe impossible to train with current technology but those things could happen and it could theoretically be mayonnaise
matter and energy tell spacetime how to curve. Curved spaceime tells matter and energy how to move
AI doesn't have to become conscious to change civilization. It only has to become competent.
Bob1:20:54
Figures
| Quantum tunneling wait time | septillion to the septillion years | 31:17 |
| Space needed for zero-point energy to light a bulb | several cubic light-years | 23:16 |
| Share of stellar observations inferred from gravity | 90% | 25:16 |
| Years the Roman telescope's fuel can hold its position | 10 years | 50:35 |
| Precision of the matching fall rates of the rubidium clouds | five parts in ten million | 1:04:44 |
| Year the crewed capsule is launched in the Verne novel | 1865 | 1:16:52 |
| Year Mark Twain wrote the teleoscope short story | 1898 | 1:18:54 |
| Publication year of Edward Bellamy's novel Looking Backward | 1888 | 1:19:54 |
Glossary
- physical reservoir computing
- Treating any nonlinear physical system as a neural network and reading off its computational capacity.
- island of stability
- A predicted region in nuclear physics where superheavy elements might be stable.
- coronagraph
- An instrument that blocks a star's glare to directly image the planets around it.
- contingent learning
- The way infants learn by kicking a leg to establish a causal link with a moving object.
- big rip
- The hypothesis that dark energy makes cosmic expansion run away and eventually tears apart all structure.
How to listen
For listeners who like science-fiction premise-building and progress in space telescopes and robot learning; founders can skip the first-half riffing and go straight to the technical details in the second half.
The change-a-law-of-physics riffing from 2:07–23:16, unless you only want the jokes.