forall x v1.4

The new edition of forall x will be posted soon. Anybody who has used the book before will find the changes so small as to make almost no difference, but I wanted to discuss what I did beyond correcting typos. First, I’ve changed the formatting a bit. Second, I’ve changed the notation for substitution instances in proofs (again). Third, I’ve changed the license to be even more permissive.

1. Formatting: I’ve moved some tables around jazzed up the chapter headings.


Universal Introduction and Elimination
Rules for the universal quantifier, using the new notation.


2. Notation: I released the previous version (1.30) after the last time I taught logic. I had been unhappy with the notation for substitution instances, but I hadn’t tried teaching with the revised version until this Fall. I stepped in to teach the last two weeks of somebody else’s logic course, and I found that the v1.30 notation was awkward for me and meaningless to the students.

So I’m replacing v1.30’s box-and-arrow notation with something that looks more like a regular formula.1

3. License: For the original edition back in 2005, I opted for a Noncommercial license (CC BY-SA-NC). That restriction ruled out some remix uses, for people who wanted to combine material from my book with material under other open licenses. So I changed to the more permissive Sharealike license (CC BY-SA) which allowed commercial use on the condition that people shared their derivative works under a similar open license.

Many Open Education Resources require an even more permissive license (CC BY).2 Richard Zach recently asked if I’d allow parts of forall x to be incorporated into the Rebus Introduction to Philosophy. I said yes, but he had to ask because Rebus uses a CC-BY license.

My original aim in adopting a Creative Commons license and sharing the book on-line was to let people use what I made in their own ways. I adopted a more restrictive license back then because I didn’t want the book to be repackaged and sold like just another logic book. There were enough of those already.

Now it seems as if awareness of OER is sufficiently widespread that there’s not too much danger of that. Maybe somebody will try to profit off my work in exploitive ways, but lots of people will share it, remix it, and use it for good.

  1. The metavariables are used in a somewhat slippery way. Usually the script letters would mean a whole formula followed by a term, but here it means a formula containing the term. It’s intuitive, though, and that’s better for an introductory book than something formally correct but mystifying.
  2. Sometimes this is a funder mandate. Open SUNY books, for example, are under a CC-BY license.

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