Epochs and slots all the way down

Vitalik Buterin argues that Ethereum's slot-and-epoch architecture is hard to avoid, because reaching approximate agreement takes less time than reaching economic finality. He describes Ethereum L1 transactions as confirming within 5-20 seconds today, while Gasper finality takes 12.8 minutes after two epochs. He proposes exploring based preconfirmations, promoted by Justin Drake, in which proposers sell immediate guarantees of inclusion, and notes that a 1-second slot time would shrink the case for separate L2 committee preconfirmations.