How Do Proof-of-Stake (PoS) Systems Achieve Economic Finality Differently than PoW Systems?

PoS systems achieve economic finality through the concept of "stake finality," which is based on a supermajority (e.g. 2/3rds) of the total staked capital explicitly agreeing on a block.

Unlike PoW, which relies on the probabilistic cost of energy, PoS relies on the direct economic disincentive of "slashing." If a validator attempts to create a conflicting chain, their staked collateral is seized by the protocol. This direct, deterministic penalty provides a stronger and faster form of economic finality than the probabilistic finality of PoW.