What Is the Difference between “Probabilistic Finality” and “Absolute Finality” in Blockchains?

Probabilistic finality, typical of PoW chains, means a transaction is considered final with a high probability that increases with each subsequent block. It is never 100 percent certain, but the cost of reversal quickly becomes prohibitive.

Absolute finality, common in PoS and BFT-style chains, means that once a transaction is confirmed, it is mathematically guaranteed to be irreversible, often within seconds. This difference is critical for high-value financial applications.