Part 2: Technical Overview

Weak Subjectivity

The two great problems that had to be solved in order for proof of stake to be a sound foundation for the world's economic activity were (1) the nothing at stake problem, and (2) long range attacks.

Ethereum's consensus solves the nothing at stake problem – that it is costless for a proof of stake validator to equivocate on every block proposal, building on every fork rather than picking one – with a slashing mechanism. The long range attack problem is solved by embracing weak subjectivity.

TODO