Controversy and Competition

At this point you might be wondering: Why do we need so many different consensus algorithms? Which one works better? The answer to the latter question is at the center of the most exciting area of research in distributed systems of the past decade. It all boils down to what you consider “better”—which in the context of computer science is about assumptions, goals, and the unavoidable trade-offs.

It is likely that no algorithm can optimize across all dimensions of the problem of decentralized consensus. When someone suggests that one consensus algorithm is “better” than the others, you should start asking questions that clarify: Better at what? Immutability, finality, decentralization, cost? There is no clear answer to these questions, at least not yet. Furthermore, the design of consensus algorithms is at the center of a multi-billion-dollar industry and generates enormous controversy and heated arguments. In the end, there might not be a “correct” answer, just as there might be different answers for different applications.

The entire blockchain industry is one giant experiment where these questions will be tested under adversarial conditions, with enormous monetary value at stake. In the end, history will answer the controversy.