What Is ‘Probabilistic Finality’ in PoW?

Probabilistic finality means that a transaction is never 100% final but becomes exponentially more final as more blocks are mined on top of it. In PoW, a transaction is considered secure after a certain number of confirmations (e.g. six blocks).

While a chain re-organization is theoretically possible, the economic cost and computational power required to reverse a transaction after many confirmations make the probability of reversal negligible.