Who can change the rules

Wonder

1. Why does a change in Bitcoin require voluntary adoption by thousands of independent operators, while an Ethereum upgrade can be coordinated by a core team?
2. What is the operational difference between a chain that forks its history and one that halts entirely?
3. How does the ability to pause a network translate into the power to censor specific transactions?

Explore

1. Bitcoin’s rules are encoded in open-source code, but they function as agreed-upon social contracts. Changes require wide voluntary adoption by node operators; there is no central foundation with authority to force an upgrade. If a proposed change lacks near-unanimous support from the network’s participants—miners, nodes, and users—it risks splitting the system into two competing chains. This decentralized governance model ensures that no single entity can unilaterally rewrite history, making contested changes historically difficult to implement without consensus.
2. Ethereum operates differently. The Ethereum Foundation and core developers coordinate upgrades on a regular schedule, maintaining a strong culture of community verification while allowing for more centralized coordination than Bitcoin. In July 2016, following the DAO hack, the network hard-forked to move the drained funds to a recovery contract, an irregular change to the chain’s state. This demonstrated that Ethereum’s rules could be changed by the developers if the community agreed, establishing a precedent that chain history is mutable through coordinated consensus rather than immutable fact.
3. Many newer chains introduce centralized control mechanisms for stability or security. A foundation, company, or small validator set can often upgrade, pause, or halt the network entirely. This capability provides rapid response to bugs or exploits but concentrates power in few hands. The trade-off is clear: efficiency and recoverability come at the cost of decentralization. Users on these chains must trust that the controlling entity will not abuse its authority, a significant departure from the permissionless models pioneered by Bitcoin.
4. The ability to halt a chain is functionally equivalent to the ability to censor it. If validators can stop block production or reverse state transitions, they can also prevent specific transactions from being included. In October 2022, BNB Chain’s validators halted the network following a bridge hack, freezing assets and allowing for recovery. While this prevented total loss of user funds, it underscored that the entity controlling the halt button controls the flow of value. This centralized control is a deliberate design choice present in many modern Layer-1 architectures.
5. Governance models vary widely across the ecosystem. Some chains use on-chain voting where token holders directly propose and pass changes; others rely on off-chain developer coordination with social consensus; still others grant ultimate authority to a corporate entity. Each model presents distinct risks: on-chain voting can be captured by large holders, developer coordination can become oligarchic, and corporate control introduces counterparty risk. Understanding who holds the keys to rule changes is essential for evaluating the long-term security and neutrality of any blockchain network.
6. To evaluate governance, examine the mechanism for consensus changes. Check if a single entity or small group can force a fork or halt. Review historical forks: were they driven by community dissent or developer coordination? Look at the validator set size; smaller sets imply higher centralization and easier halting. Finally, inspect the codebase for ‘pause’ functions or admin keys. These technical artifacts reveal the true distribution of power, often differing significantly from a project’s public claims about decentralization.

Key facts

Exercise nine, six, three, one

Fact check

Dates, figures and claims checked against the published sources listed below.

• Ethereum Foundation, 'Hard Fork Completed' (20 Jul 2016)
• The Register, 'Binance bridge hack siphons about $566 million of BNB tokens' (7 Oct 2022)
• Bitcoin Core documentation on the BIP process and consensus rules