## 7/17/2008

### Are offprints obsolete?

In my department mailbox, I just found a big package, shipped over from Germany, containing 50 copies of a recent article of mine. This struck me as a waste of paper and postage, especially given the unbelievable subscription prices for some for-profit academic journals. I reckon that cutting out offprint services wouldn't save that much money, but lowering the prices even a little might increase access somewhat for institutions that are smaller or in developing countries.

And I personally have never sent anyone a preprint, and never received one. Every paper I've exchanged long-distance has been via email.

Perhaps things are different in other academic fields, but given my limited experience, offprints seem pretty obsolete. (That said, I do like receiving a physical paper copy of the journal issue where my article appears, but I think this is primarily because it somehow feeds my pridefulness and vanity.)

Are there reasons in favor of continuing the status quo offprint practices? If so, I'd like to hear them.

## 7/10/2008

### Are truth-value gluts necessary to avoid explosion?

Before I get to the question in the title of the post, let me give a quick rehearsal of some uncontroversial material, for readers innocent of this particular topic. In classical logic, anything follows from a contradiction:
A & ~A, ∴ B
is a valid argument. This argument form is known as ex falso quodlibet (EFQ); Graham Priest calls it 'explosion.' This clearly runs counter to our intuitions about what follows from what: it just doesn't seem like '2+2=200' follows from 'Grass is green and grass is not green.' Yet it does in classical logic.

Because this seems counterintuitive, people have devised logics in which EFQ is not a valid argument form. The most prominent is the family of relevance logics. So relevance logics score a point because they fit our intuitions about EFQ.

How do relevance logics avoid EFQ? Semantically/ Model-theoretically, they allow 'truth-value gluts', that is, a sentence can be both true and false. Now we can see why (A & ~A), ∴ B is invalid in logics allowing gluts: assign A both true and false, and assign B false. Then all the premises are true and the conclusion is not true.

That was all set-up. Now the question: suppose it turns out that there are no truth-value gluts, i.e., no sentence (or proposition or whatever) is both true and false. Would (some) defenders of relevance logics then accept EFQ? Well, perhaps all the glut people need is that gluts are possible, and not that actually some sentence is both true and false. Then my question would be: would EFQ-deniers accept EFQ if gluts were impossible? From my limited exposure to the literature (Priest, C. Mortensen NDJFL 1983), it seemed like the answer might be yes, because they say things like 'Disjunctive Syllogism (which is valid classically but not relevantly) is valid in all consistent reasoning-contexts.' I would've hoped that we could discard EFQ without taking on such a contentious idea as truth-value gluts...

And a further question just out of ignorance: does anyone characterize logical validity in such a way that it (i) avoids EFQ and (ii) does not require truth-preservation? I don't see any other way besides gluts to declare EFQ invalid, if we stick to the standard characterization of validity.

## 7/07/2008

### In Praise of Graham Priest's Intro to Non-Classical Logic

This summer, I am directing an independent study on non-classical logics. In part because of Ole's glowing recommendation, the primary text has been Graham Priest's Introduction to Non-Classical Logic. The book has been fantastic; I can recommend it without qualification. It is pitched at just the right level for a philosophy student with maybe one logic course under their belt -- neither too slow nor too quick. The end-of-chapter exercises are also just right: neither too difficult nor too easy. And each chapter closes with a couple of pages dealing with how the technical material presented there connects up with overtly philosophical questions, keeping up motivation for people whose primary interest is not in the formal/ mathematical side of things.

Another aspect of the book that appealed to me was that (partial) soundness and completeness proofs were given at the end of each chapter, separated from the main course of discussion as optional material. Such proofs are of course incredibly important to practicing logicians, but I sometimes think that the amount of time and effort needed for them is better spent elsewhere given the limitations of a classroom, and the fact that most philosophy students in logic classes won't go on to be practicing logicians. The nice thing about Priest's presentation is that if you think soundness and completeness proofs are essential, you can cover them, or if (like me) you'd rather spend that time covering a wider array of logics, you can easily skip over them without loss or inconvenience.

Last but not least, I certainly have learned a thing or two (or ten), even though it is labeled as an introductory textbook. I will definitely use this book again in future classes.

## 7/01/2008

### committing armchairs to the flames

I have an avid spectator's interest in experimental philosophy, and do not pretend to expertise. I've recently seen, on email lists and blogposts, announcements for an experimental philosophy workshop called Armchair in Flames? It looks like an interesting conference; but a thought popped into my head about the title, which refers to the X-Phi anthem (performed here ).

Experimental philosophers take themselves to be committing the philosophical armchair to the flames, because (in part) they do surveys of the person-in-the-street's view on various philosophical topics. They thus test whether what professional philosophers say is commonsensical really is common sense, or rather some sort of idiosyncrasy or professional deformation.

But I just wanted to remark that this is only one way of committing the armchair to the flames. Another, which has been the dominant outlook in philosophy of science for the last few decades, is to discount heavily or even completely any deliverances of so-called common sense or intuition, and instead lean heavily or even completely upon the deliverances of mature sciences in formulating philosophical positions. This outlook was unequivocally in full effect in the department where I got my PhD, among faculty and students alike.

So in short, the experimental philosophers don't have a monopoly on casting armchairs into the flames -- the philosophers of science have been stoking that fire for a while already.