Why it is a question
Simoes, Dastani and van Ommen (2025), LIT-1802, show that at full causal control the causal information bottleneck is optimised by the partition of X by p(y | do(x)) (THEORY-1125), and that projected gradient search found it in 95 to 100 percent of runs on three toy models whose X has at most 16 values (THEORY-1146). The search needed ensembles of 4 to 12 optimisers and a penalty against unused values of T, and the authors expect local minima to need “modifications” at scale. They do not claim that it scales.
What would answer it
Results on causal systems larger than toy SCMs, with confounding and a known causal partition, in which the information bottleneck at full sufficiency recovers the observational partition by p(y | x) and the causal bottleneck, computed through an adjustment set, recovers the partition by p(y | do(x)), reliably and with the optimiser’s failure rate reported; or a case where the observational and causal partitions differ and the causal bottleneck does not find the latter.