This is my edition of the open source forall x logic textbook, which I use in my introductory logic class at Syracuse University. It is based on Tim Button's forall x: Cambridge, which is in turn based on P.D. Magnus' original forall x. The present text is licensed under a CC BY-SA 4.0 license.
The main changes I've made compared to forall x: Cambridge are the following:
- I've changed the first chapter to more closely reflect my own introductory lecture. For example, I elucidate the modal notion of validity using possible worlds, and emphasize logic's focus on formal validity a bit more.
- I've added more on the semantics of truth-functional and especially first-order logic, particularly as concerns the construction of countermodels.
- I've made some changes to set of natural deduction rules in both parts.
- I've reordered the presentation of various topics and revised the practice problems.
For more information, see https://mrieppel.net/teaching