Vitalik Buterin embraces ‘mountain man’ verification as zk-proofs mature on Ethereum

Vitalik Buterin reverses his 2017 stance, arguing zk-proofs now make “mountain man” full verification a real fallback as Ethereum stress-tests decentralization.

Ethereum (ETH) co-founder Vitalik Buterin has publicly walked back a long‑standing critique of “mountain man” full verification, arguing that advances in zero‑knowledge proofs and a harsher view of real‑world failure modes now justify much stronger user‑level guarantees than he once thought realistic. “I no longer agree with this previous tweet of mine – since 2017, I have become a much more willing connoisseur of mountains,” he wrote, revisiting a debate that has haunted blockchain design for nearly a decade.

From Grigg’s minimalist chain to Merkle roots

Buterin’s original position emerged in a 2017 clash with financial cryptographer Ian Grigg, who argued that blockchains should “track the order of transactions, but not the state (eg. user balances, smart contract code and storage).” In Grigg’s model, “the messages are logged, but the state (e.g., UTXO) is implied, which means it is constructed by the computer internally, and then (can be) thrown away.”

Buterin says he opposed that philosophy because it forces users either to “run a node that processed every transaction in all of history, or trust someone else.” Instead, Ethereum commits state directly in block headers so “you can simply prove any value in the state with a Merkle branch,” under an honest‑majority assumption where “if >= 50% of the consensus participants are honest, then the chain with the most PoW (or PoS) support will be valid.”

What changed, in his telling, is the maturation of ZK‑SNARKs. “We now have a technology that lets you verify the correctness of the chain, without literally re-executing every transaction,” Buterin wrote. “WE INVENTED THE THING THAT GETS YOU THE BENEFITS WITHOUT THE COSTS!” He likens this to “a clearly working pill that anyone could make for $15 that cured all diseases,” arguing that if such a pill existed, “healthcare becomes super affordable so everyone is happy.”

Zero‑knowledge systems already underpin zk‑rollups that compress transaction data and offload computation while preserving verifiability, allowing millions of computation steps to be checked “in a very fast way” without redoing the work. For Buterin, this eliminates much of the old block‑size tradeoff: scalability no longer has to mean blind trust in intermediaries.

Equally important is a shift from academic models to messy reality. “In the real world, lots of things break,” he concedes, listing p2p outages, latency spikes “from its usual ~200ms to 1000–5000ms,” centralized staking, and censorship, including Tornado Cash, where “your only option becomes to directly use the chain.” In that world, “THE ANSWER TO THE ABOVE CONUNDRUMS CANNOT ALWAYS BE ‘CALL THE DEVS’,” he warns, arguing that developers themselves risk becoming a central point of control.

Instead, Buterin reframes the “Mountain Man’s cabin” as a BATNA – a “Best Alternative to a Negotiated Agreement” – that users may rarely inhabit but must know exists. “We do not need to start living every day in the Mountain Man’s cabin,” he writes. “But part of maintaining the infinite garden of Ethereum is certainly keeping the cabin well-maintained.”

Buterin’s rethink lands in a market that continues to price Ethereum as critical settlement infrastructure. Ether trades today around 2,922.90 dollars, up roughly 0.34% over the last 24 hours, with daily volume above 25.4 billion dollars. Bitcoin remains the bellwether above 70,000 dollars on major venues, while large caps like Solana and other smart‑contract platforms show low‑single‑digit percentage moves over the same period, reflecting a market that increasingly prices execution, censorship‑resistance, and verification assurances as core fundamentals rather than ideology.