# Seminar in Semantics / Philosophy of Language # or: **What Philosophers and Linguists Can Learn From Theoretical Computer Science But Didn't Know To Ask** This course will be co-taught by [Chris Barker](http://homepages.nyu.edu/~cb125/) and [Jim Pryor](http://www.jimpryor.net/). Linguistics calls it "G61.3340-002" and Philosophy calls it "G83.2296-001." ## Announcements ## The seminar meets on Mondays, starting September 13, from 4-6. The first meeting will be in the Linguistics building at 10 Washington Place on the first floor (room 104). (Earlier, we were going to meet in the 2nd floor Philosophy Seminar Room, at 5 Washington Place, but there were conflicts.) We may be able to shift the time around slightly to suit the schedule of participants; but it will remain on Mondays late afternoon/evenings. ## Assignments ## [[Assignment1]] ## Overview ## The goal of this seminar is to introduce concepts and techniques from theoretical computer science and show how they can provide insight into established philosophical and linguistic problems. This is not a seminar about any particular technology or software. Rather, it's about a variety of conceptual/logical ideas that have been developed in computer science and that linguists and philosophers ought to know, or may already be unknowingly trying to reinvent. Philosphers and linguists tend to reuse the same familiar tools in ever more (sometime spectacularly) creative ways. But when your only hammer is classical logic, every problem looks like modus ponens. In contrast, computer scientists have invested considerable ingenuity in studying tool design, and have made remarkable progress. "Why shouldn't I reinvent some idea X for myself? It's intellectually rewarding!" Yes it is, but it also takes time you might have better spent elsewhere. After all, you can get anywhere you want to go by walking, but you can accomplish more with a combination of walking and strategic subway rides. More importantly, the idiosyncrasies of your particular implementation may obscure what's fundamental to the idea you're working with. Your implementation may be buggy in corner cases you didn't think of; it may be incomplete and not trivial to generalize; its connection to existing literature and neighboring issues may go unnoticed. For all these reasons you're better off understanding the state of the art. The theoretical tools we'll be introducing aren't very familiar to everyday programmers, but they are prominent in academic computer science, especially in the fields of functional programming and type theory. Of necessity, this course will lay a lot of logical groundwork. But throughout we'll be aiming to mix that groundwork with real cases in our home subjects where these tools play central roles. Our aim for the course is to enable you to make these tools your own; to have enough understanding of them to recognize them in use, use them yourself at least in simple ways, and to be able to read more about them when appropriate. Once we get up and running, the central focii of the course will be **continuations**, **types**, and **monads**. One of the on-going themes will concern evaluation order and issues about how computations (inferences, derivations) unfold in (for instance) time. The key analytic technique is to form a static, order-independent model of a dynamic process. We'll be discussing this in much more detail as the course proceeds. The logical systems we'll be looking at include: * the pure/untyped lambda calculus * combinatorial logic * the simply-typed lambda calculus * polymorphic types with System F * some discussion of dependent types * if time permits, "indeterministic" or "preemptively parallel" computation and linear logic ## Who Can Participate? ## The course will not presume previous experience with programming. We will, however, discuss concepts embodied in specific programming languages, and we will encourage experimentation with running, modifying, and writing computer programs. The course will not presume lots of mathematical or logical background, either. However, it will demand a certain amount of comfort working with such material; as a result, it will not be especially well-suited to be a first graduate-level course in formal semantics or philosophy of language. If you have concerns about your background, come discuss them with us. This class will count as satisfying the logic requirement for Philosophy PhD students; however if this would be your first or only serious engagement with graduate-level formal work you should consider carefully, and must discuss with us, (1) whether you'll be adequately prepared for this course, and (2) whether you'd be better served by taking a logic course (at a neighboring department, or at NYU next year) with a more canonical syllabus. Faculty and students from outside of NYU Linguistics and Philosophy are welcome to audit, to the extent that this coheres well with the needs of our local students. ## Recommended Software ## During the course, we'll be encouraging you to try out various things in Scheme and Caml, which are prominent *functional programming languages*. We'll explain what that means during the course. * **Scheme** is one of two major dialects of *Lisp*, which is a large family of programming languages. The other dialect is called "CommonLisp." Scheme is the more clean and minimalistic dialect, and is what's mostly used in academic circles. Scheme itself has umpteen different "implementations", which share most of their fundamentals, but have slightly different extensions and interact with the operating system differently. One major implementation used to be called PLT Scheme, and has just in the past few weeks changed their name to Racket. This is what we recommend you use. (If you're already using or comfortable with another Scheme implementation, though, there's no compelling reason to switch.) * **Caml** is one of two major dialects of *ML*, which is another large family of programming languages. The other dialect is called "SML" and has several implementations. But Caml has only one active implementation, OCaml, developed by the INRIA academic group in France. * Those of you with some programming background may have encountered a third prominent functional programming language, **Haskell**. This is also used a lot in the academic contexts we'll be working through. Its surface syntax differs from Caml, and there are various important things one can do in each of Haskell and Caml that one can't (or can't as easily) do in the other. But these languages also have a lot in common, and if you're familiar with one of them, it's not difficult to move between it and the other. [[How to get the programming languages running on your computer]] [[Using the programming languages]] [[Family tree of functional programming languages]] ## Recommended Books ## * *An Introduction to Lambda Calculi for Computer Scientists*, by Chris Hankin, currently $17 on [Amazon](http://www.amazon.com/Introduction-Lambda-Calculi-Computer-Scientists/dp/0954300653). * (Another good book covering the same ground as the Hankin book, but more thoroughly, and in a more mathematical style, is *Lambda-Calculus and Combinators: an Introduction*, by J. Roger Hindley and Jonathan P. Seldin. If you choose to read both the Hankin book and this book, you'll notice the authors made some different terminological/notational choices. At first, this makes comprehension slightly slower, but in the long run it's helpful because it makes the arbitrariness of those choices more salient.) * *The Little Schemer, Fourth Edition*, by Daniel P. Friedman and Matthias Felleisen, currently $23 on [Amazon](http://www.amazon.com/exec/obidos/ASIN/0262560992). This is a classic text introducing the gentle art of programming, using the functional programming language Scheme. Many people love this book, but it has an unusual dialog format that is not to everybody's taste. **Of particular interest for this course** is the explanation of the Y combinator, available as a free sample chapter [at the MIT Press web page for the book](http://www.ccs.neu.edu/home/matthias/BTLS/). * *The Seasoned Schemer*, also by Daniel P. Friedman and Matthias Felleisen, currently $28 on [Amazon](http://www.amazon.com/Seasoned-Schemer-Daniel-P-Friedman/dp/026256100X) * *The Little MLer*, by Matthias Felleisen and Daniel P. Friedman, currently $27 on [Amazon](http://www.amazon.com/Little-MLer-Matthias-Felleisen/dp/026256114X). This covers some of the same introductory ground as The Little Schemer, but this time in ML. The dialect of ML used is SML, not OCaml, but there are only superficial syntactic differences between these languages. [Here's a translation manual between them](http://www.mpi-sws.org/~rossberg/sml-vs-ocaml.html). ##[[Schedule of Topics]]## ##[[Lecture Notes]]## ##[[Offsite Reading]]## There's lots of links here already to tutorials and encyclopedia entries about many of the notions we'll be dealing with. ---- All wikis are supposed to have a [[SandBox]], so this one does too. This wiki is powered by [[ikiwiki]].