Step 6 / The Bitcoin Machine
Who can change the rules?
Publishing new rules does not make everyone else follow them.
Imagine a developer publishes software that gives miners a much larger reward. Anyone can see the new code. But other computers are still running the old reward rule.
If a miner tries the larger reward, those unchanged computers reject it. Writing a new rule and getting other people to adopt it are different steps.
Rules decide what is allowed; work helps choose a history
Think of validation rules as a rulebook. They say which proposed blocks a node can accept. Among histories that follow that rulebook, the node uses chain-selection rules to choose which history to follow.
A constitution is a useful comparison: it sets out which actions are permitted. Choosing among permitted actions is another job. But the comparison has limits. Bitcoin nodes are not courts, and proof of work is not an election where each person casts a vote.
Making more usernames or running more node addresses does not rewrite another node’s rules. Changing your own copy of the code does not change theirs either. A block with an excessive reward remains invalid to nodes that keep the original rule, even if it has proof of work.
Different roles have different choices
Developers can propose changes and publish software. They cannot install it on everyone’s computer or force everyone to accept it. Node operators choose the software and rules they run.
Miners choose which blocks they try to produce. Users and businesses choose which systems they use. These groups can influence one another, so coordination matters. Influence is not the same as one person giving an order that all must obey.
A written change proposal may be published as a Bitcoin Improvement Proposal, or BIP. This records the idea. It does not automatically endorse or install it.
To judge a proposed change, look at its actual rules for being introduced. Then ask who has chosen to use those rules. Publication and adoption are different kinds of evidence.
What if people keep different rules?
Some changes narrow what is allowed while keeping new blocks within what older software accepts. This is called a soft fork. The rules become stricter.
Other changes can allow blocks that older rules reject. This is called a hard fork. If groups keep operating with incompatible rules, they can continue along separate histories.
Copying or changing software is called a code fork. That alone does not create a lasting network. People must keep running it, checking and producing its history, and finding it useful.
A well-known founder or an impressive technical paper cannot supply that continued use by itself. The software design and people’s decisions about using it both matter.
A shared rulebook is an analogy. Publication of an amendment alone does not establish adoption.
The idea to keep
Ask who proposes software, who checks blocks, who produces them, and who chooses to use the network. One job title does not describe every kind of power. A participant may have strong influence without being able to command everyone else.
Next, apply that distinction to Bitcoin’s supply rule: what halves, who checks the limit, and why the schedule does not decide the price.