Why the existing families do not close it
| Family | Failure mode at scale |
|---|---|
| Regularisation (EWC and descendants) | Stiffness accumulates; plasticity approaches zero |
| Replay | Storage grows with stream length, or generation quality degrades |
| Parameter isolation | Parameter count grows with task count; transfer is lost |
| Retraining from scratch | Cost grows with total experience; not a continual method |
The trilemma is the point: bounded parameters, bounded storage, and bounded forgetting appear to be jointly unachievable by current methods, and nobody has shown they are jointly unachievable in principle either.
What would count as progress
A demonstration on a stream long enough that the failure modes above actually bite — which in practice means months, not the short task sequences standard in the literature. An honest negative result on a year-long stream would also close a real gap.