He seems to suggest that "humans = chimps + X", therefore what makes intelligence must be a subset of "X", therefore rather small.
Which in my opinion is wrong. Imagine that to make intelligence, you need A and B and C and D. Chimps have A and B and C, but they don't have D. Humans have A and B and C and D, which is why humans are more intelligent than chimps. However, having D alone, without A and B and C, would not be sufficient for intelligence.
The fact that the DNA distance between humans and chimps is small only proves that if we tried to make chimps smarter by genetical engineering, we wouldn't have to change most of their genes. But that is irrelevant for making a machine. We don't have fully chimp-level machines yet.
Folks here should be familiar with most of these arguments. Putting some interesting quotes below:
http://aeon.co/magazine/being-human/david-deutsch-artificial-intelligence/
"Creative blocks: The very laws of physics imply that artificial intelligence must be possible. What's holding us up?"
He also says confusing things about induction being inadequate for creativity which I'm guessing he couldn't support well in this short essay (perhaps he explains better in his books). Not quoting here. His attack on Bayesianism as an explanation for intelligence is valid and interesting, but could be wrong. Given what we know about neural networks, something like this does happen in the brain, and possibly even at a concept level.
His final conclusions are disagreeable. He somehow concludes that the principal bottleneck in AGI research is a philosophical one.
In his last paragraph, he makes the following controversial statement:
This would be false if, for example, the mother controls gene expression while a foetus develops and helps shape the brain. We should be able to answer this question definitively once we can grow human babies completely in vitro. Another problem would be the impact of the cultural environment. A way to answer this question would be to see if our Stone Age ancestors would be classified as AGIs under a reasonable definition