In that article, the author claims that a human brain cannot create something more intelligent than itself, and argues by saying that over several billion years

In that article, the author claims that a human brain cannot create something more intelligent than itself, and argues by saying that over several billion years of evolution, no human brain has ever done so, thus it must not be possible. That argument is totally nonsense. A hundred years ago, you could argue that humans cannot invent an internet, because over billions of years (minus one hundred), it's never happened. There's a more rigorous way to argue for the claim in question, which debuted in my doctoral dissertation. Or, not quite the exact claim in question, but rather the following claim: that an idealized mechanical knowing agent cannot create a more intelligent idealized mechanical knowing agent than itself (at least, not one which it can actually trust). The idea behind the proof is quite simple, but requires familiarity with computable ordinal numbers. If knowing agent X creates knowing agent Y, then presumably X knows Y's sourcecode. Thus, X can infer a sourcecode for the list of all naturals n such that Y knows "n is the code of a computable ordinal". If X actually trusts Y, then X knows that whenever Y knows "n is the code of a computable ordinal", then n really is the code of a computable ordinal. Combining these, X can infer the ordinality of the ordering obtained by concatenating together all the ordinals which Y knows are ordinals. Thus, X knows a larger computable ordinal than all the computable ordinals Y knows. Which, depending on your definition of intelligence, arguably suggests X is more intelligent than Y.