In fact, at time of writing, "natural language understanding" is still on the Wikipedia page for AI-complete.
> Intelligence has yet to be accurately defined --- and there is no reason to believe it is a statistical function
Other than the work of Rev. Bayes, Prof. Schrödinger. Plus, now I think about it, saying "randomness can't lead to intelligence" is the talking point for all the people who insist Darwin is wrong and there has to be an intelligent designer.