Bitcoin is Circular and Works

What is Bitcoin?

Bitcoin is a ledger with a clever incentive.

Here’s the problem it solves: how do you maintain a shared database without a central authority? Who decides what’s true? Who prevents cheating?

Traditional answer: trust someone. A bank. A government. A company.

Bitcoin’s answer: trust math and incentives.

Bitcoin Is a Public Ledger of Every Transaction

Bitcoin maintains a ledger of balances. Alice has 5 coins. Bob has 3. When Alice sends 2 to Bob, the ledger updates. Alice now has 3, Bob has 5.

The ledger is public. Everyone can see every transaction ever made. No secrets.

Without Authority, Who Prevents Lies?

If there’s no central authority, who updates the ledger? And how do you prevent someone from lying about the updates?

If I run a copy of the ledger, what stops me from claiming I have a million coins?

Mining: Solve Puzzles to Update the Ledger

Groups of transactions are bundled into blocks. To add a block to the ledger, you have to solve a computational puzzle. The puzzle is hard to solve but easy to verify.

This is called mining. Miners compete to solve puzzles. The winner adds the next block.

Why would anyone do this? Because the winner gets paid in newly created coins. This is where new bitcoins come from.

The Currency Incentivizes Honest Maintenance

Here’s the key insight: the currency itself incentivizes honest maintenance of the ledger.

If you’re a miner, you want your coins to be valuable. You only get paid if other people accept your blocks as legitimate. If you cheat (if you try to double-spend or create invalid transactions) other miners reject your blocks. You spent the electricity for nothing.

The currency creates the incentive to maintain the ledger that tracks the currency. It’s circular, but it works.

Bitcoin Proved Currencies Can Exist Without Trust

Before Bitcoin, digital currencies required trust. Someone had to run the server. Someone had to prevent double-spending.

Bitcoin showed that a currency could exist without trusted parties. Just math, incentives, and a network of self-interested participants.

Whether that’s useful for money specifically is debatable. That it’s possible at all is the breakthrough.