I had a mild disagreement with climate scientist William Connolley here on my use of the term 'plagiarism'. He objected that the articles in question did mention that they 'incorporate' material from the Catholic Enyclopedia. This is a matter of semantics. To my mind the word 'incorporates' suggests 'proper subset of' rather then 'equals', but let's pass over that. It matters in a very real way that the magic of crowdsourcing is little more than indiscriminate copying of the scholarship of a century ago.
The article Durandus misses all the medieval scholarship that happened from around 1913 until now. In the case of medieval studies, that is quite a lot. The discipline did not really get started until the nineteenth century, and much of the primary source material - the works themselves - did not become available until well into the twentieth century. (Indeed, the work that Jack and I are currently translating did not become available in a critical edition until a few years ago, and has never been published in English).
Thus the Wikipedia article necessarily misses some important facts. For example, that Durandus was one of those assigned by John XXII to investigate Ockham’s nominalism. Or the centrality of his work on the category of relation – first highlighted by Koch in 1927. The article does not even mention the dates of Durandus’ work (the first Sentences commentary between 1303-8, the second between 1310-12) and omits to mention a number of his other works. As any scholar knows, assigning a date to a source is of crucial importance, and is a painful business. Wikipedia, which is good at basic facts, and lists of things, would be an ideal source of such information. But it isn't.
You will say I am knocking Wikipedia again. But the point underlying this is not to knock Wikipedia, but rather a false claim about 'crowdsourcing'. We should be thanking the scholars of 100 years ago for Wikipedia, not the crowd (or Jimmy Wales, who is supposed to have invented the whole thing).