LibraryConsensus1998Design paperCorpus record
The Part-Time Parliament
Paxos. Leslie Lamport.
A value is chosen only when a majority has accepted it in some ballot, and every higher ballot must honour a value that majority might already have chosen.
A reading of the public document. Not a copy of it, and not a claim about a later network that reused the name.
When a system says it is Paxos, ask which ballot can override which value, and whether a learner waits for a majority.
The five-minute read
The defect
A legislature that is often absent still has to pass one sequence of decrees.
The rule
A value is chosen only when a majority has accepted it in some ballot, and every higher ballot must honour a value that majority might already have chosen.
How it is put together
Ballots are totally ordered. A majority quorum prepares, then accepts. Learners act only after they see a majority.
Where the claim stops
Paxos does not pick an open membership.
One action, walked through
- Prepare asks a quorum to stop accepting lower ballots.
- Accept proposes a value consistent with the promises just collected.
- Two majorities intersect, so two chosen decrees cannot disagree.
- Is the quorum a majority of a known set?
The argument, unpacked
Why it is still on the desk
When a system says it is Paxos, ask which ballot can override which value, and whether a learner waits for a majority.
After the text
Multi-Paxos, Chubby and Raft are engineering accounts of this shape. A stake-elected validator set is a different membership problem sitting in front of it.
What has to be true
- Paxos does not pick an open membership.
- It is not Raft's replicated log, though Raft is a later explanation of a similar idea.
- It does not set fees, blocks, or a coin.
What happened after the paper
Multi-Paxos, Chubby and Raft are engineering accounts of this shape. A stake-elected validator set is a different membership problem sitting in front of it.
What to check before you use the idea
- Is the quorum a majority of a known set?
- Can a higher ballot abandon a value a majority already accepted?
- Who is allowed to learn, and on what evidence?
Terms
- Ballot
- A numbered attempt to choose one value.
- Majority
- Any two majorities share at least one replica.
The problem the paper names
A legislature that is often absent still has to pass one sequence of decrees.
What the design proposes
- Ballots are totally ordered.
- A majority quorum prepares, then accepts.
- Learners act only after they see a majority.
How the mechanism is specified
- Prepare asks a quorum to stop accepting lower ballots.
- Accept proposes a value consistent with the promises just collected.
- Two majorities intersect, so two chosen decrees cannot disagree.
What this page does not treat as proven
- Paxos does not pick an open membership.
- It is not Raft's replicated log, though Raft is a later explanation of a similar idea.
- It does not set fees, blocks, or a coin.
Why a venture studio still reads it
When a system says it is Paxos, ask which ballot can override which value, and whether a learner waits for a majority.
This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.
Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.