Author Archives: Peter Smith

Spam, spam, spam, spam, …

[Reposted/updated from thirty months ago.] There are only two options for any blog. Allow no comments at all; or have a spam-filter that filters what goes into the moderation queue. No way can you moderate by hand all the comments … Continue reading

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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

Posted in IFL, Logic | 4 Comments

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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The language(s) of first-order logic #2

One theme touched on the last post is whether the language for our preferred natural deduction system syntactically distinguishes symbols used as parameters in (UI) and/or (EE) proofs. Of the nine books I mentioned, two use distinct symbols for parameters, … Continue reading

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The language(s) of first-order logic #1

In presenting a formal theory of first-order logic for an introductory course — or, in my case, an introductory book — there are a lot of choices to be made, even once we’ve fixed on using a natural deduction proof system. (This paper by … Continue reading

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Truth trees for propositional logic

I’ve revised (and of course revised again, and re-revised!) the chapters on truth-trees for propositional logic for the second edition of my intro logic text. What took four chapters and forty pages has now become two chapters and twenty-eight pages, … Continue reading

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Conditionals, yet again

It’s very predictable, I would imagine, that some of the chapters that have been giving me the most grief as I write the second edition of my logic text are the two chapters where I introduce the material conditional. In the last … Continue reading

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Holiday readings

Here are three suggestions for fun holiday reading — none of them new books, as it happens, but ones I’ve particularly enjoyed in the last few weeks. So, warmly recommended if you haven’t yet read them and are looking for pleasing distractions: Robert … Continue reading

Posted in This and that | 3 Comments