Vitalik
https://blog.ethereum.org/2016/06/19/thinking-smart-contract-security/

"However, it does show that there is a fundamental barrier to what can be accomplished, and “fairness” is not something that can be mathematically proven in a theorem"

well yes it can:

If you hold a system will function in a particular way and it does then that is fair, and you can mathematically prove it
https://www.reddit.com/r/ethereum/comments/4opjov/the_bug_which_the_dao_hacker_exploited_was_not/
TL;DR - Complexity and "Turing completeness" are not the real culprit here - those are all good things that we can have someday. The real culprit is poor language design. Specifically, I would recommend using "functional" (rather than "procedural") languages for mission-critical code which will be driving "smart contracts" - and even better if a high-level "specification" language could be used, allowing formal derivation of a (verifiably correct) program in a low-level "implementation" language (ie, providing mathematical proof that the implementation satisfies the specification - and mitigating the problem where the high-level human-readable "description" is different from the low-level machine-runnable "code").

When I read Vitalik, its boils down to semantics, buzz words and a spin not hard logic/maths, contra vitalik to the white paper of satoshi. Satoshi is almost all business and proofs.

Vitalik is obviously good at galveinsing capital behind a project and networking with people, just not so much as CEO of a code based contracts system it seems, as he does not have the understanding to select the coding team and understand what they tell him.