*summum genus*of all

*genera*, is likely to be the worst. And a real stinker, too.

Now William Connolley “British software engineer, writer, and blogger on climate science” has had a go. I generally appreciate Connolley’s contributions to Wikipedia. He has worked hard to reinforce rational and reasonable and ‘scientific’ approach to articles on science and junk science and pseudoscientific nonsense generally, and that is not so bad. But his attempts at improving “Existence” perfectly illustrate the problem when people who are intelligent and articulate but educated in one subject area try to tackle another subject in which they are perhaps not so competent.

I was intrigued by his edit here where he removes a brief discussion of the existential quantifier which explains how mathematicians would express ‘a four-leaf clover exists’ by defining Px as ‘x is clover’, Qx as ‘x has four leaves’ and writing ‘Ex Px & Qx’. This is essentially correct but Connolley removes it with the wonderful comment “this article is essentially entirely about philosophical goo and dribble. lets not taint it with anything like maths”. Oh dear. You learn from even the most basic acquaintance with the history of logic that existence is one of those questions that lie at its core. As I have occasionally said, e.g. here, the question of whether ‘some A is B’ is equivalent to ‘some A-B exists’ was resolved by Brentano, further developed by Peirce and Frege – who were philosophers or mathematicians or both - and that this was an important, perhaps the most important, contribution to the development of ‘mathematical logic’ in the mid-19th century. Even Wikipedia (see e.g. the articles on mathematical logic and particular on the history of quantification) is pretty clear about this.

Another irritation is Connolley’s remark about ‘goo and dribble’ – he means ‘philosophy’. ‘Existence’ is difficult not just because it has a long and complex history in philosophy, with a close affinity to other subjects like philosophy of language, Aristotelian logic and mathematical logic. Like philosophy in general, the subject is connected in the popular imagination with non-scientific subjects like mysticism, meditation, crystals and suchlike. But that is something else.

*Metaphysica sunt, non leguntur*.

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