A "meta ledger" to resolve fragmentation of proof-of-work Nakamoto consensus
The Nakamoto consensus is meant to be singular, it is how it generates immutability, and it was when Satoshi employed it for the Bitcoin ledger in 2009. With innovations in digital ledger technology, Nakamoto consensus has become fragmented as miners are now mining on lots of different ledgers. This can be resolved by introducing a new innovation, a “meta ledger”, that provides a form of “general purpose mining”. This "meta ledger" only does immutability and nothing else. It only stores the merkle root of hash proofs from ledgers that employ it, with no self-interest to store anything more. No token, no state transitions, no timestamps and no validation. Only proof-of-work, pure, raw immutability. PoW[n] = hash(PoW[n-1] + merkle root[n] + nonce[n]). Keep it simple. The idea of a “meta ledger” is that other ledgers compete to employ it based on their ability to pay for its service - immutability - and that the payments are issued on these "sub ledgers". This turns the organization upside down, ledgers no longer compete for miners, they compete to pay the miners on the “meta ledger”. This “meta ledger” centralizes employment opportunity for miners as it provides the highest possible immutability.
Nakamoto consensus has to be singular for immutability
The Nakamoto consensus is meant to be singular. Unless or until there is one-ledger-to-rule-them-all, it makes sense from a security and immutability PoV to pool all ledgers under one “meta ledger”. This “meta ledger” as a singular Nakamoto consensus can gradually evolve into a singular ledger (by pruning merkle tree of ledgers it notarizes until only one leaf remains and this leaf becomes merkle root), rather than the other way around, a singular ledger evolving into a singular Nakamoto consensus. This creates the ultimate "leader" for the developing web 3.0 ecosystem, a singular, global, fully autonomous and perfectly neutral coordinating mechanism. "General purpose mining". This "meta ledger" has no scalability issues as it only cares about immutability by proof-of-work, and stores only a hash and a nonce per "block".
Validation, censorship resistance, and mining pools
Mining pools that Satoshi predicted have already abstracted miners from validation and censorship resistance. Only the admin of the pool actually validates, the miners do pure immutability. Validation of the ledger has the benefit that failed validation can be proven, anyone can publish the proof and notify the "public". To offload immutability to a "meta ledger" and leave validation to some other entity, is not necessarily a bad idea. The censorship resistance is still an issue, but, censorship likely has much much lower economic gains than 51% attacks, and it might still not be idea to have a dedicated "immutability" notary. If this "meta ledger" published every 10 minutes, and merkle root and nonce are 256 bit each, it takes up 3 mb per year, and can provide immutability for entire world.
Ledger merkle tree
A very simple way for users to validate the "meta ledger" and sub ledgers is ledger merkle trees. Each user requests the root hash, and, to validate it, they request a random block, and merkle proofs, after they have recieved the root hash. If proof-of-work is on average 10 minutes, they would be certain they received a block that had been worked on already and that has merkle proofs that fit to the root hash. A universal source of truth reduced down to a single hash.
