I’m not an expert in human evolution, but the failure of an aquatic lifestyle to explain our large brains, our bipedalism and, importantly, the lack of evidence that hominins didn’t live in aquatic habitats during the time that important features of our body developed—all this counts against the Aquatic Ape Hypothesis. ...He cites John Hawks who wrote an essay last year on Why anthropologists rejected the aquatic ape theory.
As far as I can see, scientists did take the aquatic theory seriously, but rejected it based on the preponderance of evidence. The accusation that scientists are suppressing novel and counterintuitive evidence out of a group desire to avoid major paradigm changes in their field is one sign of pseudoscience.
These are informed comments, but I do not find them convincing. First they say that the theory was oversold, and cannot explain all the things that its proponents claim. Second, anthropologists study fossils and aquatic apes do not leave fossils, so researchers have not been making progress on the theory. Third, the hypothesis seems implausible.
Okay, but that does not mean the hypothesis is false. It explains some things better than the competing theories. Even if the theory seems implausible, it seems to me that researchers should take it seriously and compare against it, when they discuss alternative theories. That is, they should find a theory that works better.