Yearly Archives: 2017

A more natural Disjunction Elimination rule?

We work in a natural deduction setting, and choose a Gentzen-style layout rather than a Fitch-style presentation (this choice is quite irrelevant to the point at issue). The standard Gentzen-style disjunction elimination rule encodes the uncontroversially valid mode of reasoning, … Continue reading

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MA Scholarship in Logic/Phil Math (Montreal)

Ulf Hlobil writes: “At Concordia University (Montreal), we want to do something about the gender imbalance in philosophy.  We offer specialized scholarships for female international students who are working ancient philosophy or logic and philosophy of mathematics.  Each scholarship is … Continue reading

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The Great Formal Machinery Works

I’d like to have had the time now to carefully read Jan von Plato’s new book and comment on it here, as the bits I’ve dipped into are very interesting. But, after a holiday break, I must get my nose … Continue reading

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Postcard from the Lake District

After a week in the Lakes, here’s a photo taken walking back from Howtown to Pooley Bridge above Ullswater. Beautiful. Worries about Trump, Brexit, and even Begriffsschrift seem happily remote.

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Begriffsschrift and absolutely unrestricted quantification

We owe to Frege in Begriffsschrift our modern practice of taking unrestricted quantification (in one sense)  as basic. I mean, he taught us how to rephrase restricted quantifications by using unrestricted quantifiers plus connectives in the now familiar way, so that … Continue reading

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Jeanne Moreau, 23.i.1928 – 31.vii.2017

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Which is the quantifier?

A note on another of those bits of really elementary logic you don’t (re)think about from one year to the next – except when you are (re)writing an introductory text! This time, the question is which is the quantifier, ‘’ or ‘’, ‘’ or ‘’? Really exciting, … Continue reading

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Ivana Gavrić, Chopin

I’ve very much admired Ivana Gavrić previous rightly praised discs (I wrote about the first two here in an earlier post, and you can find more about  them here). So I was really  looking forward to hearing her play in the intimate surroundings of the Fitzwilliam Museum in … Continue reading

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Why mandatory reiteration in Fitch-style proofs?

Digressing from issues about the choice of language(s), another post about principles for selecting among natural deduction systems — another choice point, and (though I suppose relatively minor) one not considered by Pelletier and Hazen. Take the most trite of examples. It’s … Continue reading

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The language(s) of first-order logic #3

Back to those choice-points noted in the first of these three posts: one formal language for FOL or many? Tarski or quasi-substitutional semantics? use of symbols as parameters as opposed to names or variables to be syntactically marked? In the second … Continue reading

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