Open questions
What is not settled, and what would settle it
The program's main results are walls as well as theorems, and the walls point at the questions that matter. These are the ones currently open, stated so that each could be settled.
The story so far
- Patterns split by sizeAny pattern across switches is a sum of pieces, one per group.
- Depth fixes what is visibleA depth-t observer sees exactly the pieces of size t or less.
- More depth, or more observers, sees moreA strict ladder, and windows that can be pooled.
- Measurement erases the quantum sideThe interface keeps the visible part and deletes coherence.Wall: hidden structure cannot become visible inside this interface.
- Filtering gives a sign patternOne kept direction, the rest discarded: plus, minus, minus, minus.Wall: algebra alone is not physical spacetime.
- Many cells give a geometryCoupled cells have long-wavelength modes with a natural notion of distance.Wall: positive couplings spread like ink, not like light.
- Which quantum state is selected?The classical rules fix the visible part but not the quantum interior.
Which quantum interior does nature pick?
The program's classical rules fix what an observer sees on average, but many different quantum states agree with those rules. Something else must choose among them.
- Known
- The usual candidates fail in exact ways: shaking the system, symmetry, and agreement on visible data alone all fail to choose. Numerical evidence Requiring neighbouring observers to stay consistent strongly favours two-way couplings.
- Would settle it
- A proof that consistency forces the coupling to be two-way, and a principle that picks which two-way coupling.
Can what is hidden for one observer be visible to another?
Inside the program's measurement interface, provably not. A doorway between observers would need a new kind of structure, and it has to be derived rather than assumed.
- Known
- The interface no-go, and a symmetry argument showing that relabelling every observer the same way changes nothing.
- Would settle it
- A derived rule for how neighbouring observers' frames connect, with something measurable when you go around a loop.
Does spacetime emerge from observers?
The algebra produces the right sign pattern and a Lorentz-type algebra, but every dynamics tested so far fails to turn these into physical motion through space.
- Known
- Several precise no-go results: fixed-depth counting is not four-dimensional causal structure; single scalar couplings cannot lock internal directions to space; a light cone appears only when a coupling is tuned by hand.
- Would settle it
- A rule, derived from the observer axioms, for how cells glue together into a large-scale, direction-free whole.
Can observers share one clock?
Three observers share a single time only if going around the loop between them leaves no leftover lag. The criterion is proved; the program does not yet have a correlated three-observer state to test it on.
What do correlations of the whole add?
A rule that observers can never know more than half of a hidden state reproduces much of quantum behaviour, but no rule of that kind can reach the correlations seen in entangled pairs. Whether the program's whole-only structure accounts for the difference is a question, not a result.