*forallx: Cambridge* is a
textbook for introductory formal logic. It is the textbook we use for
the Cambridge Part IA formal logic course. It covers both truth-functional logic and first-order logic, introducing students to semantics and to a Fitch-style natural deduction system. The textbook contains numerous exercises, for which there is a complete solutions booklet.

Given the license, you can print as many copies as you like, or use the source code to make derivative works, provided you respect various conditions. But if you do use the book, please let P.D. Magnus and me know!
P.D. Magnus can be contacted at fecundity.com/logic/; I can
be contacted at *tecb2* at *cam* dot *ac* dot
*uk*. (Please also get in touch if you think you have spotted a mistake.)

*forallx: Cambridge* pdf

*forallx: Cambridge* LaTeX source code

Solutions booklet pdf

Solutions booklet LaTeX source code

The book is based upon P.D. Magnus’s *forallx*
(available at fecundity.com/logic/).
Magnus very generously made his book available under
a Creative Commons license. This licenses derivative work, and the
text was altered for the Cambridge Course. *forallx: Cambridge*
is now released under the
same license. In brief, this means that you can
use the texts free of charge. But you can also download the source
files, make changes to them, and make a version of the textbook
suitable for your own requirements.

If you are interested in teaching from an opensource textbook, take a look at both Magnus’s original text, and at the Cambridge version. There are substantive differences in the order in which material is presented. There are also points at which the material differs, in particular:

**Use/Mention**. The Cambridge version discusses the distinction between use and mention, and enforces strict quotation rules.**Semantics**. Magnus has a chapter discussing formal set-theoretic semantics for both TFL and FOL. This has been removed from the Cambridge version, and replaced with something a little bit lighter.**Proof system**. Both books use a Fitch-style natural deduction system. However, the system for the Cambridge version has rules governing the introduction and elimination of ‘⊥’, and is designed so that deleting a single rule yields intuitionistic logic. This makes it easier for students to explore non-classical logics, later in life. The Cambridge version also has an appendix, discussing different but equivalent natural deduction systems.**Plurals**. The Cambridge version eschews all talk of sets in favour of plural-locutions. So we say that some sentences are*jointly inconsistent*, rather than saying that a*set*of sentences is inconsistent.**Solutions**. The Cambridge version comes with a solutions booklet for all the practice exercises in the book. This allow for students to mark their own work.**Metatheory**. The textbook*Metatheory*continues on from the Cambridge version. This explores the metatheory of the truth-functional systems presented in the Cambridge version of*forallx*.

I would like to repeat my thanks to P.D. Magnus. He has been extraordinarily generous, in making *forallx* available to everyone. I hope that other logic teachers will be inspired by his generosity, and will continue to build upon this foundation.

*forallx: Cambridge* is based upon P.D. Magnus’s *forallx* (version 1.29), available at fecundity.com/logic, which was released under a Creative Commons license (Attribution-ShareAlike 3.0).

You are free to copy this book, to distribute it, to display it, and to make derivative works, under the following conditions: (a) Attribution. You must give the original author credit. (b) Share Alike. If you alter, transform, or build upon this work, you may distribute the resulting work only under a license identical to this one.

For any reuse or distribution, you must make clear to others the license terms of this work. Any of these conditions can be waived if you get permission from the copyright holder. Your fair use and other rights are in no way affected by the above.

This is a human-readable summary of the full license, which is available on-line at creativecommons.org.

In accordance with this license, Tim Button has made changes to P.D. Magnus’s original text, and added new material. He offers *forallx: Cambridge* under the same Creative Commons license.

Last modified 29 Oct 2015