Ethereum (ETH) co-founder Vitalik Buterin has reversed his 2017 position that dismissed full blockchain self-validation by users as a "weird mountain man fantasy," citing advances in ZK-SNARK cryptography and lessons from real-world network failures as reasons for the shift.

What Happened: Buterin Reverses Stance

Buterin announced his change in thinking in a recent post on X. The statement directly contradicts his position from nearly eight years ago.

In 2017, Buterin debated blockchain theorist Ian Grigg over whether blockchains should commit to state on-chain. Grigg argued that blockchains could log transaction order without storing user balances, smart contract code, or storage.

Buterin opposed this approach at the time, warning that users would either have to replay the entire chain history or fully trust third-party RPC providers. He called both options impractical for average participants.

What changed his mind is the development of ZK-SNARKs.

This cryptographic breakthrough allows users to verify the correctness of the blockchain without re-executing every transaction.

"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!"

Buterin compared the innovation to discovering a "pill that cures all diseases for $15."

Also Read: Bitget TradFi Volume Doubles To $4B In Just 13 Days

Why It Matters: Network Resilience

Buterin emphasized practical concerns about centralization and network reliability. "Sometimes the P2P network goes down. Sometimes latency spikes 20x. Sometimes a service you rely on shuts down," he wrote.

He added that miners or stakers sometimes concentrate power and intermediaries censor applications. In such scenarios, users must retain the ability to directly verify and use the chain without outside assistance.

"If we are making a self-sovereign blockchain to last through the ages, THE ANSWER TO THE ABOVE CONUNDRUMS CANNOT ALWAYS BE 'CALL THE DEVS,'" Buterin wrote. "If it is, the devs themselves become the point of centralization."

Buterin now advocates for what he calls the "Mountain Man" option. While full self-verification is not meant for daily use, it serves as a critical fallback.

He compared it to how BitTorrent constrained streaming platforms to offer better terms to consumers. The option provides leverage and security amid technological and political uncertainty.

Buterin now advocates for what he calls the "Mountain Man" option as a fallback rather than daily practice. "We do not need to start living every day in the Mountain Man's cabin," he wrote. "But part of maintaining the infinite garden of Ethereum is certainly keeping the cabin well-maintained."

Read Next: Winter Storm Knocks 110 EH/s Off US Bitcoin Mining