The essay does take advantage over the common "naturalistic fallacy", where people imply something as being "good" from its being "natural". As a simple counterexample, many diseases are "natural" and many antibiotics, not.
However, I think it's only fair that Paul's motivation for some of his essays is, at least in part, PR work for YC, and hence the fibs (that being the harshest word I'd use) are understandable.
This is not a "naturalistic fallacy" (more properly called an appeal to nature), because PG uses "natural" in the very narrow sense of "evolutionarily optimal". PG must have thought his target audience is discerning enough to dereference such things without any hand-holding.
> The essay does take advantage over the common "naturalistic fallacy", where people imply something as being "good" from its being "natural".
The essay avoids that fallacy by making the case that humans, having evolved under certain social conditions, might be much better equipped at present to cope with similar conditions. This itself may be true or false, but it is not fallacious reasoning.
However, I think it's only fair that Paul's motivation for some of his essays is, at least in part, PR work for YC, and hence the fibs (that being the harshest word I'd use) are understandable.