Suppose that you have some background in classical first-order logic, and want to learn something about modal logic (including quantified modal logic) and, relatedly, about Kripke semantics for intuitionistic logic. Then the second half of Sider’s *Logic for Philosophy* certainly aims to cover the ground, and it will tell you about formal theories of counterfactuals too. How well does it succeed, especially if you skip the first half of the book and dive straight in, starting with Ch. 6?

These later chapters in fact seem to me to work fairly well (assuming a logic-competent reader). Compared with the early chapters with their inconsistent levels of coverage and sophistication, the discussion here develops more systematically and at a reasonably steady level of exposition. There is a lot of (acknowledged) straight borrowing from Hughes and Cresswell, and student readers would probably do best by supplementing Sider with a parallel reading of that approachable classic text. But if you want a pretty clear explanation of Kripke semantics together with an axiomatic presentation of some standard modal propositional systems, and want to learn e.g. how to search systematically for countermodels, Sider’s treatment could well work as a basis. And then the later treatments of quantified modal logic (and some of the conceptual issues they raise) are also lucid and tolerably approachable.

This is a game of two halves then. Before the interval, *Logic for Philosophy* is pretty scrappy and I wouldn’t recommend it. After the interval, when Sider plays through some standard modal logics, things look up. I wouldn’t have him at the top of the league for modality-for-philosophers (see the current version of the Guide for preferred recommendations); but Sider’s book-within-a-book turns in a respectable performance.

Rowsety MoidI’d like to hear more from students. The book gets good reviews on Amazon, and I wonder how much difference it makes to most students exactly how technical details such as the Ps and Qs are handled.

There are similar problems in teaching programming languages. For instance, do we say that ‘x’ is a variable, or the name of a variable, or what? There are different ways to handle the details, some better than others, but I think they play a relatively minor role in giving students understanding. It’s almost the other way around: they learn primarily by doing, working with the various constructs and seeing how they behave, and that helps them understand the technical details. I don’t think maths and logic are very different.

I’m not saying it doesn’t matter if the technical details are muddled, or wrong, or not formulated and expressed in the best way; and I’m not questioning the view that other books do a better job than Sider’s; but I do wonder whether the book’s really so bad from a student’s point of view.

Peter SmithDavid’s comment seems quite telling on this score. Not that I think that the book is positively bad on FOL — it is quite attractively written in some ways. But my first impressions when I saw draft chapters which Sider posted some time ago were disappointing; and I still don’t think it is the book that philosophers (especially those who aren’t too hot at maths) will want.

Daniel NagaseWell, I still stand by what I said in the other post. I’m definitely not “hot” at math (and, indeed, I didn’t particularly like the first chapter of the book). But I found the presentation of propositional logic very useful (including his preference for so-called “Hilbert systems”, which helped me understand why so many textbooks prefer this approach). As for the part about FOL, I think he wrote just enough for me to understand what I believe is the crucial step beyond propositional logic, which is the semantics, in particular the notion of satisfaction. And it was enough for me to get hooked on the subject, fwiw.

Rowsety MoidDavid’s comment doesn’t say whether the pedagogical fixes were necessary because the students struggled or became confused, or because he was acting in advance to head off confusion or (for example) to present things in a better way that would be confusing when combined with the unfixed book.

(BTW, it was tricky to reply to your post after it already had a reply — I had to open the reply link in another window — and I’m not sure whether this will appear in the right place. I had the same problem with both Firefox and Chrome on a Mac.)

David AuerbachWell, it was two years ago. And it is good to remember that my classes have a wide variation within the class (I get philosophy majors, math students (who don’t know much about proof), comp. sci., stragglers from other STEM disciplines, etc.), and variation year to year as to population. There’s a sort of cohort phenom. BUT, as I recall, I had to do a lot of filling in the blanks about the sketchier technical stuff, supplemental drilling on just mechanics as well as (but I’m cranky about such) use/mention stuff. It wasn’t smooth. I’ve been through many a book in this course (both the baby logic and the advanced logic* courses are far easier) and for *my* students Sider just didn’t work. I liked the idea (including not just FOL=) but it just didn’t work. I’m much happier with Bostock. (I remain a real fan of Suppes, and may go back to that with supplements to clean up his semantics and offer an alternate proof system. But I like that ancient book because it aims at one of my major goals in my intermediate logic course–relating formal proofs to informal (i.e., actual) proofs.

*(B&J, 3rd edition)

David AuerbachI actually tried using the book for my Intermediate Logic course; things went precisely as Peter’s review would suggest. The only really useful segment was the countermodel part. Much time was spent on pedagogical fixes for the first part.

This semester I’ve gone back to FOL using Bostock, which, with some quibbles, is much much better for my students.

Rowsety MoidSo there are better alternatives to the first part, and better alternatives to the second part (though not as much better), but is there a better, single-book alternative to the book as a whole?

Peter SmithWell, I can’t think of a book with just this coverage which is better. But could having first order logic and modal logic between a single pair of covers trump having a first-rate treatment of the former by using two books?