Ha good point :) I don't think it's a joke, I think he is falling into the same fallacy himself. To be fair, the article acknowledges it's a difficult trap: "We seem ill-equipped to deal mentally with a continuous spectrum of intermediates. We are still infected with the plague of Plato’s essentialism." He would probably agree, if someone pointed it out to him, that his phrasing here was an example of exactly what he's talking about. I think it is just a fault of phrasing though; it doesn't really undermine the sentiment of the article. It almost vindicates it!
>>> We seem ill-equipped to deal mentally with a continuous spectrum of intermediates. We are still infected with the plague of Plato’s essentialism.
This is contradictory. If we have some kind of mental handicap that not allows us to perceive spectra properly, it's wrong to blame Plato for this. If, however, Plato is the one who steered the whole civilization wrong, that means we are capable of doing better - we just don't do it right now. Of course, it could be that it's both but Plato and mental handicap together wouldn't allow us to realize it :) Recursion is recursive.
> If we have some kind of mental handicap that not allows us to perceive spectra properly, it's wrong to blame Plato for this.
I think Dawkins is simply using Plato's idea as an intellectual roadsign, not assigning moral responsibility. If I refer to Karl Popper when discussing falsifiability, I might simply be providing a convenient reference to the idea, not holding Popper responsible for the idea (which he isn't).
I think since he discusses the essentialism as an idea that needs to be dropped, he goes further than that - he seems to blame Plato (at least among others) for "infecting" us (taken broadly) with the essentialism. After all, the idea of essentialism has to come from somewhere, somebody had to invent it. To me, Dawkins assigns the fault for it to Plato. He does it in the very first sentence - "Essentialism—what I’ve called "the tyranny of the discontinuous mind"—stems from Plato".
Again, describing the origin of an idea isn't the same as assigning responsibility. Your use of words like "blame", "infecting" and "fault", and the associated tone, simply have no parallel in the article.
Also, correlation is not causation. Many of these classic ideas, found in the writings of Plato, Aristotle and others, were as much responses to the prevailing ideas of the time as they were a source or inspiration for those ideas. Our modern perspective is distorted by the fact that we may have only one writer's record of the ideas of a time, which may mislead us into thinking that particular writer originated the idea instead of reporting it.
"Infecting" is a direct quote from "We are still infected with the plague of Plato’s essentialism." and Dawkins uses the same word at least twice more.
>>> Our modern perspective is distorted by the fact that we may have only one writer's record of the ideas of a time, which may mislead us into thinking that particular writer originated the idea instead of reporting it.
This very well may be true, but since we and Dawkins share this perspective, and Dawkins offers no other suggestion and no other name but Plato and does not consider the possibility that this perspective might be wrong in any way, I think the conclusion that he operates on the assumption that this perspective - attributing essentialism to Plato - is correct would not be illogical, at least when we consider this particular article.
We are mentally equipped partially by our culture and our education. I don't know that Dawkins is committed to the notion that it is nature more than nurture that equips us poorly, though I admit I've only given the article a cursory skim.
