1 # Seminar in Semantics / Philosophy of Language #
3 or: **What Philosophers and Linguists Can Learn From Theoretical Computer Science But Didn't Know To Ask**
5 This course is co-taught by [Chris Barker](http://homepages.nyu.edu/~cb125/) and [Jim Pryor](http://www.jimpryor.net/). Linguistics calls it "G61.3340" and Philosophy calls it "G83.2296"
6 The seminar meets in spring 2015 on Thursdays from 4-7, in
7 the Linguistics building at 10 Washington Place, in room 104 (back of the first floor).
10 One student session will be held every Wednesday from 3-4 on the
11 fourth floor at 10 Washington Place.
17 This wiki will be undergoing lots of changes throughout the semester, and particularly in these first few days as we get it set up, migrate over some of the content from the previous time
18 we taught this course, and iron out various technical wrinkles. Please be patient.
20 If you've eager to learn, though, you don't have to wait on us to be ready to serve you. You can go look at the [archived first version](http://lambda1.jimpryor.net) of this course. Just keep in mind that
21 the text and links there haven't been updated.
26 The goal of this seminar is to introduce concepts and techniques from
27 theoretical computer science and show how they can provide insight
28 into established philosophical and linguistic problems.
30 This is not a seminar about any particular technology or software.
32 Rather, it's about a variety of conceptual/logical ideas that have been
33 developed in computer science and that linguists and philosophers ought to
34 know, or may already be unknowingly trying to reinvent.
36 Philosphers and linguists tend to reuse the same familiar tools in
37 ever more (sometime spectacularly) creative ways. But when your only
38 hammer is classical logic, every problem looks like modus ponens. In
39 contrast, computer scientists have invested considerable ingenuity in
40 studying tool design, and have made remarkable progress.
42 "Why shouldn't I reinvent some idea X for myself? It's intellectually
43 rewarding!" Yes it is, but it also takes time you might have better
44 spent elsewhere. After all, you can get anywhere you want to go by walking, but you can
45 accomplish more with a combination of walking and strategic subway
48 More importantly, the idiosyncrasies of your particular
49 implementation may obscure what's fundamental to the idea you're
50 working with. Your implementation may be buggy in corner cases you
51 didn't think of; it may be incomplete and not trivial to generalize; its
52 connection to existing literature and neighboring issues may go
53 unnoticed. For all these reasons you're better off understanding the
56 The theoretical tools we'll be introducing aren't very familiar to
57 everyday programmers, but they are prominent in academic computer science,
58 especially in the fields of functional programming and type theory.
60 Of necessity, this course will lay a lot of logical groundwork. But throughout
61 we'll be aiming to mix that groundwork with real cases
62 in our home subjects where these tools play central roles.
65 course is to enable you to make these tools your own; to have enough
66 understanding of them to recognize them in use, use them yourself at least
67 in simple ways, and to be able to read more about them when appropriate.
70 Once we get up and running, the central focii of the course will be
71 **continuations**, **types**, and **monads**. One of the on-going themes will
72 concern evaluation order and issues about how computations (inferences,
73 derivations) unfold in (for instance) time. The key analytic technique is to
74 form a static, order-independent model of a dynamic process. We'll be
75 discussing this in much more detail as the course proceeds.
77 The logical systems we'll be looking at include:
79 * the pure/untyped lambda calculus
81 * the simply-typed lambda calculus
82 * polymorphic types with System F
83 * some discussion of dependent types
84 * if time permits, "indeterministic" or "preemptively parallel" computation and linear logic
88 recursion using the Y-combinator
89 evaluation-order stratgies
90 normalizing properties
91 the Curry-Howard isomorphism(s)
92 monads in category theory and computation
95 ## Who Can Participate? ##
97 The course will not presume previous experience with programming. We
98 will, however, discuss concepts embodied in specific programming
99 languages, and we will encourage experimentation with running,
100 modifying, and writing computer programs.
102 The course will not presume lots of mathematical or logical background, either.
103 However, it will demand a certain amount of comfort working with such material; as a result,
104 it will not be especially well-suited to be a first graduate-level course
105 in formal semantics or philosophy of language. If you have concerns about your
106 background, come discuss them with us.
109 This class will count as satisfying the logic requirement for Philosophy
110 PhD students; however if this would be your first or only serious
111 engagement with graduate-level formal work you should consider
112 carefully, and must discuss with us, (1) whether you'll be adequately
113 prepared for this course, and (2) whether you'd be better served by
114 taking a logic course (at a neighboring department, or at NYU next year)
115 with a more canonical syllabus.
118 Faculty and students from outside of NYU Linguistics and Philosophy are welcome
119 to audit, to the extent that this coheres well with the needs of our local
123 ## Recommended Software ##
125 During the course, we'll be encouraging you to try out various things in Scheme
126 and Caml, which are prominent *functional programming languages*. We'll explain
127 what that means during the course.
129 * **Scheme** is one of two major dialects of *Lisp*, which is a large family
130 of programming languages. Scheme
131 is the more clean and minimalistic dialect, and is what's mostly used in
133 Scheme itself has umpteen different "implementations", which share most of
134 their fundamentals, but have slightly different extensions and interact with
135 the operating system differently. One major implementation used to be called
136 PLT Scheme, and has just in the past few weeks changed their name to Racket.
137 This is what we recommend you use. (If you're already using or comfortable with
138 another Scheme implementation, though, there's no compelling reason to switch.)
140 Racket stands to Scheme in something like the relation Firefox stands to HTML.
142 * **Caml** is one of two major dialects of *ML*, which is another large
143 family of programming languages. Caml has only one active implementation,
144 OCaml, developed by the INRIA academic group in France.
146 * Those of you with some programming background may have encountered a third
147 prominent functional programming language, **Haskell**. This is also used a
148 lot in the academic contexts we'll be working through. Its surface syntax
149 differs from Caml, and there are various important things one can do in
150 each of Haskell and Caml that one can't (or can't as easily) do in the
151 other. But these languages also have a lot in common, and if you're
152 familiar with one of them, it's not difficult to move between it and the
156 <a name=installing></a>
157 [[How to get the programming languages running on your computer]]
159 [[Family tree of functional programming languages]]
161 [[Translating between OCaml Scheme and Haskell]]
163 ## What is Functional Programming? ##
165 Here's a [survey conducted at Microsoft](http://research.microsoft.com/apps/pubs/default.aspx?id=141506) asking programmers what they understand "functional programming" to be. Don't take their responses to be authoritative... this is a just a "man in the street" (seat?) poll.
167 Read more about the [uptake of Haskell](http://steve-yegge.blogspot.com/2010/12/haskell-researchers-announce-discovery.html) among programmers in the street.
170 ## Recommended Books ##
172 It's not necessary to purchase these for the class. But they are good ways to get a more thorough and solid understanding of some of the more basic conceptual tools we'll be using.
174 * *An Introduction to Lambda Calculi for Computer Scientists*, by Chris
175 Hankin, currently $17 on
176 [Amazon](http://www.amazon.com/dp/0954300653).
178 * (Another good book covering the same ground as the Hankin book, but
179 more thoroughly, and in a more mathematical style, is *Lambda-Calculus and Combinators:
180 an Introduction*, by J. Roger Hindley and Jonathan P. Seldin, currently $52 on [Amazon](http://www.amazon.com/dp/0521898854). If you choose to read
181 both the Hankin book and this book, you'll notice the authors made some different
182 terminological/notational choices. At first, this makes comprehension slightly slower,
183 but in the long run it's helpful because it makes the arbitrariness of those choices more salient.)
185 * (Another good book, covering some of the same ground as the previous two, but also delving much deeper into typed lambda calculi, is *Types and Programming Languages*, by Benjamin Pierce, currently $61 on [Amazon](http://www.amazon.com/dp/0262162091). This book has many examples in OCaml.)
187 * *The Little Schemer, Fourth Edition*, by Daniel P. Friedman and Matthias
188 Felleisen, currently $23 on [Amazon](http://www.amazon.com/exec/obidos/ASIN/0262560992).
189 This is a classic text introducing the gentle art of programming, using the
190 functional programming language Scheme. Many people love this book, but it has
191 an unusual dialog format that is not to everybody's taste. **Of particular
192 interest for this course** is the explanation of the Y combinator, available as
193 a free sample chapter [at the MIT Press web page for the
194 book](http://www.ccs.neu.edu/home/matthias/BTLS/).
196 * *The Seasoned Schemer*, also by Daniel P. Friedman and Matthias Felleisen, currently $28
197 on [Amazon](http://www.amazon.com/Seasoned-Schemer-Daniel-P-Friedman/dp/026256100X)
199 * *The Little MLer*, by Matthias Felleisen and Daniel P. Friedman, currently $27
200 on [Amazon](http://www.amazon.com/Little-MLer-Matthias-Felleisen/dp/026256114X).
201 This covers some of the same introductory ground as The Little Schemer, but
202 this time in ML. It uses another dialect of ML (called SML), instead of OCaml, but there are only
203 superficial syntactic differences between these languages. [Here's a translation
204 manual between them](http://www.mpi-sws.org/~rossberg/sml-vs-ocaml.html).
209 All wikis are supposed to have a [[SandBox]], so this one does too.
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