Consensus
Also: consensus rules
network · intermediate
The set of rules every node enforces to agree on which transactions and blocks are valid.
Bitcoin's consensus is not "miners vote." It's "every node independently rejects anything that breaks the rules." Miners produce blocks; nodes enforce. A miner who mines a block that violates consensus is ignored — the block doesn't get relayed and doesn't extend the chain.
The consensus rules cover everything: the supply schedule, the proof-of-work target, transaction validity (no double-spending, signatures must verify, scripts must succeed), block validity (size limit, valid header, valid coinbase), and the precise serialization formats of all of the above. Any disagreement on any of these rules splits the chain — there's no graceful degradation.
Consensus is emergent, not voted on. There's no membership process; nobody nominates a node to participate. People run software, and whichever rule set is enforced by an overwhelming majority of nodes and accepted by users *is* Bitcoin. Changing the rules requires changing the software running on those nodes, which is why consensus changes move slowly and conservatively.