Why Is a Longer Chain Always Considered the Canonical Chain?

The "longest chain rule" is the core of PoW consensus. It is based on the probabilistic assumption that the chain with the most cumulative Proof-of-Work (i.e. the most hashing power expended) is the one created by the honest majority.

This rule is what allows the network to converge on a single, shared history, ensuring that the double-spent transaction is eventually orphaned.

What Is the “Longest Chain Rule” and How Does It Relate to Block Confirmation?
How Does ‘Nakamoto Consensus’ Enforce the Longest Chain Rule?
What Is the “Longest Chain Rule” and Its Role in PoW Security?
How Does the Longest Chain Rule Prevent Double-Spending in PoW?
What Is the Difference between the “Longest Chain Rule” and the “Heaviest Chain Rule” in PoW?
How Does a Blockchain Resolve Temporary Forks Caused by Network Latency?
What Is the ‘Longest Chain Rule’ and Why Is It Fundamental to Nakamoto Consensus?
What Is the “Longest Chain Rule” and How Does It Prevent Confirmed Double-Spending?

Glossar