I only just discovered this. It is a Wikipedia 'Request for Comment' or RfC, which is rather like a court where Wikipedia editors pile on to each other, attack and eat their own. This one is quite extraordinary and concerns an editor 'Jagged 85' who has been systematically falsifying material in Wikipedia since he (or she) joined in 2005. The editor had a clear and consistent anti-Western agenda, systematically distorting source material in a way that untruthfully promoted Islamic (and also other non-Western) intellectual achievements, usually by claiming that a scientific developments or invention or discovery was made or anticipated by some non-Western philosopher or scientist.
It highlights a clear set of issues, as follows.
1. There is a large amount of material affected in Wikipedia, which is widely used as a reference work by millions of people, who trust it as a reliable source. The editor contributed to 8,115 pages, making 63,298 edits. Much of the problem material seems still to be there.
2. It demonstrates the role of Wikipedia in disseminating misleading and blatantly incorrect information across the web. The editor began work five years ago in December 2005, hist first edit claiming that "The Indus Valley civilization is in fact recognized as having been the first to develop urban planning. " Because many of his edits are now established, they have been reproduced and cited all over the internet. For example: Google 'Avicennian logic' (including the quotes) and it returns 6,000 sites (the top one being the Wikipedia article on 'Avicennism', where the phrase originates). Yet I am sure there is no formal system of logic known to scholars as 'Avicennian logic'. Avicenna made interesting contributions to logic, certainly, mostly in propositional logic, although this was originally developed by the ancient Greeks. But so did dozens of other middle-Eastern and Western writers, and the innovations of Avicenna do not compare in scale or impact with those of the high middle ages such as supposition theory, 'consequences' and so on. The article on 'Avicennism' says that "Avicennian logic had an influence on early medieval European logicians such as Albertus Magnus". Yet the idea that most influenced these scholars, including Albert, was Avicenna's distinction between essence and existence, which was a genuine innovation, and a departure from Aristotle. This idea had a profound impact, in different ways on Aquinas, Giles of Rome, Henry of Ghent, Scotus and eventually Ockham. But it is a metaphysical idea, not a logical one. As far as I am aware, no medieval writer discusses Avicenna's logic (as opposed to his commentary on the Metaphysics, which they frequently cite). Kneale's great work The Development of Logic mentions Avicenna twice, neither in connection with logic. Bochenski does not mention him at all. None of the articles in the main secondary sources on medieval philosophy mention Avicenna's logic (although they discuss his other achievements at length).
3. It proves a clear weakness in the Wikipedia 'verifiability principle'. The editor always provided reliable sources for their claims. However, examination revealed either blatant misrepresentation of the source, or a selective interpretation that went far beyond the author's meaning. For a long time no editors bothered to check these. The problem was amplified by his frequent use of scholarly works not available on the internet. Most of Wikipedia's editors are amateurs who have no access to a university library. Thus they cannot check a source from a journal, or an old or obscure book that would only be found in a library. Typical of his technique is this edit where he claims that "Avicenna developed an early theory of impetus, which he referred to as being proportional to weight times velocity, which was similar to the modern theory of momentum" citing Aydin Sayili (1987). "Ibn Sīnā and Buridan on the Motion of the Projectile", Annals of the New York Academy of Sciences 500. Yet the source attributes the theory to the fourteenth century French philosopher Buridan, not Avicenna. People trust Wikipedia because they believe the system of 'anyone can edit' allows for cross-checking and verification of references by a large group of users. Clearly, they should get out of this habit.