On July 20th, Vitalik Buterin replied to a social media user's inquiry about "what is a globally universal blockchain" by stating that blockchain is a "truth machine" and, in a specific sense, it provides a consensus that is close to the truth about when a message was sent, but it will not tell you if landing on the moon is true. This greatly reduces the attack surface of blockchain, but it does mean that we need other tools to actually execute (or assist) in discovering the latter truth.