The Symbolic Logic Blog

This is a location for discussion of Symbolic Logic. Comments may range from general review and evaluation of the text, to details of presentation. We can discuss substantive questions about logic too. You may submit a post of your own or add comments to another. If you require special symbols, \LaTeX code may be inserted between the markers [latex] . . . [/latex] — to start with this, see LaTeX Typing (you see the compiled result only when posted).

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SymLog hardcopy is here!

Hardcopy (paperback) versions for volume 1 and volume 2 of Symbolic Logic are now available! This most recent version of the text includes many improvements relative to previous versions.

*Amazon will raise prices for print on demand books starting June 20, 2023. Currently Symbolic Logic goes for about $10.00/volume. The cost will go up to around $14.00. This is disappointing to me insofar as I have been working with the lower price in mind. Still, either way, it remains a good deal. And the lower price is available at least for this next week.

SymLog hardcopy to come

I expect to make hardcopy (paperback) versions for Volume 1 and Volume 2 of Symbolic Logic available soon through Amazon Direct Printing (at the minimum allowable Amazon price, around $10.00/volume). Printing requires significant formatting improvements (for example, I am now staying entirely within the margins). But I have been making good progress, and expect the hardcopy versions to be available sometime in early 2023.

The .pdf download will remain free on the website. However, I do recommend working from a hardcopy and so hope a printed version will be useful to many readers.

derivations in LaTeX

I have just posted a new and (much) improved version of Typing Derivations in \LaTeX. \LaTeX is not for everyone. But using it for derivations has many advantages — especially later in the text, as derivations increase in length and complexity, something like it becomes a practical necessity.

answers to exercises

As of version 10.22, the Answers to Exercises appends answers to the main text. The main part of the text is stripped of some parts, and its formatting is affected insofar as the text and answers are on different size pages—thus it is less than ideal for ordinary reading (or printing). However, the combination of text and answers makes links between them live. This is particularly useful in later parts where there are multiple cross-references between answers and previous theorems.

As usual, I appreciate your letting me know of problems, perhaps as a comment on this post.

on electronic and printed versions of the text

I strongly recommend working from a hardcopy of SL. Somehow the ability to see more than a “screen’s worth” at a time makes a difference. Personally, I like a bound and printed (double-sided) version along with the electronic text and answers (the electronic version of the text might be single- or double-sided depending on the size of your monitor). Then you can read from the printed version, but use the electronic one to follow links, jump to answers, and so forth.

The full text is too fat to be usefully bound. Even if a printed version is not available (say as a reader from a campus bookstore), most any copy place will print and bind for you, often directly from the link. For Sentential Logic, and the two separate volumes of Symbolic Logic, you can use either “perfect” (with a tape spine) or “spiral” binding.

Of course, this costs something. But it remains a “good deal” compared to other options! T.R.

final version!?!

I have been (obsessively) proofreading Symbolic Logic for a while now. The result is many improvements, most small, but some significant. A few matters of formatting and such to the side, the current version 10.x is (at least very close to) the completed project — although, of course, it still might be improved, especially in response to your comments. But it is time for me to move on, and especially to get back to the Symbolic Logic App.

If you have downloaded a previous copy–and especially if you will take up Parts II, III, and/or IV — I strongly recommend that you obtain the new version!! T.R.

textbook commentary

It is surprising to me that the initiation of this textbook blog seems to have reduced, rather than expanded, commentary on SL (which I used to receive regularly by e-mail). It is not the case that fewer people are using the text. Perhaps the public nature the forum discourages participation? Or maybe nobody wants to be “the first”? If you have an explanation, I would love to hear. For now, I can only encourage you that I welcome comments, and that the public nature of the forum lets your discussion benefit others (and email is still fine). T.R.

SLAPP: Symbolic Logic APP

For what it is worth, I am embarked on a (long-term) project to produce an open-source computer application that would be a context for creation, submission, and correction of exercises for Symbolic Logic. If you are contemplating study of Symbolic Logic, do not “wait for it,” it will be a long time coming. However over the next years I do hope to release the program bit by bit. Among goals are,

  • Exercises are cleaner and easier (more fun) in SLAPP than on paper. (This is not trivially true – see many existing web apps.)
  • Provides contextual feedback and checking, with goal that students always complete exercises correctly – or at least know that and where they have problems.
  • Runs on as many platforms as possible – but primarily on laptop / desktop.

Quite generally, logic software is beset by a problem of resources: The market is not large enough to support full-scale commercial development (as for mathematics), and instructors may have neither the time nor training to develop full-fledged software projects on their own. I hope to overcome at least the time problem by the magic of “retirement”! T.R.

jolly good

As a retired engineer, I decided to get back to my passion of understanding ethics. Most of the works were clearly woolly and very soon I realized that I needed to enhance my skills in logic to make any headway in this direction. Most of the recent books in logic were loaded in formal mathematics and appeared way beyond my reach. It was then that Prof Roy’s book on the Internet came as a pleasant surprise. Two years later, I managed to complete most of the exercises in his book and understand the principles. It is to Prof Roy’s credit that someone like me with little training in formal mathematics can learn such a difficult subject and all along keep my interest in it without being daunted by the complexity of the subject. During this journey, Prof Roy gave his time unstintingly to respond to my queries. Nuggets of Russelian wit, veiled challenges to the daredevils, and his love for his family are sprinkled in every chapter in this book. What attracted me most were the problems at the end of each chapter; in every chapter you invariably find one which asks the student to draft a short note explaining the main ideas in the chapter in a language his teenage daughter can understand. It is well known that, if you understand something well, you ought to be able to communicate that to the non-initiated. And, equally if you teach someone what you learnt, your concepts become even clearer. As the Tamil poet says, knowledge is rare commodity that grows by giving. To recognize this and challenge the reader to try his hands at this, Prof Roy shows great intuition in the art of teaching.

As an old man living in the UK, I cannot say his book is cool, but perhaps I could say it is jolly good.  R.V.

answers to exercises

The complete answers to exercises is included in the answers version for instructors (including “hard-core” exercises later in the text). With this, it is easy for me to move answers in or out of the Selected Answers. Short of including them all, if you think some answer(s) should or should not be included among the Selected Answers, let me know. T.R.