# Category Archives: IFL

## 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 | 7 Comments

## 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

## Empty domains #1

From wild mathematical universes back to nothing much at all: the question of empty domains in first-order logic. Not that I have anything very insightful to say:  but I want to get my mind clearer before committing myself to a … Continue reading

Posted in IFL, Logic | 10 Comments

## The material conditional — analysis or replacement?

Update. I posted a couple of chapters, just 22 pages, hot off the laptop, from a bit later in the draft second edition of my Intro to Formal Logic about the material conditional. I’m now a little unhappy with them, … Continue reading

## Unsatisfying satisficing

There’s no getting away from it. You know perfectly well you can’t try to optimize a book — that way madness lies (or at least, never finishing). You know perfectly well you have to satisfice. But that is oh so … Continue reading

## Intro to Formal Logic 2nd ed. — readers wanted!

It’s not so very often in life that you get a shot at putting right something major, that first time around occupied a lot of time and energy, but didn’t turn out as well as you intended. So I’m grabbing … Continue reading