Thursday, December 18, 2014

More on third factors

Matt Husband sends me this review of a book on evolution (thx Matt). He notes its possible relevance to third factor kinds of discussions and I though you might like to take a look. Here's a short teaser blurb:

"That's not all: the structure of the library [genetic code] makes it easy for evolution to move from one meaningful book [genetic sequence] to another. When Wagner and his colleagues tried browsing adjacent "books" – proteins that differ by a single amino acid – they found that most worked just as well as the original. The same was true when they changed another amino acid, and another. In fact, you could move, step by step, from one end of the library to the other without changing the meaning.

This allows populations to accumulate a lot of genetic variation while still remaining viable. In Wagner's metaphor, readers spread into many different rooms of the library. And that's where the big pay-off comes. By wandering far afield, you come to rooms with very different sorts of books nearby. In real terms, you end up in places where changing just a few more amino acids gives you a protein with a radically different function – an evolutionary breakthrough, close at hand."

Student evaluations

These are now a big part of the promotion and tenure process. It have never been clear to me that students actually are in a position to evaluate their courses. They just don't know enough. And in the US context, evaluations, I believe, tend to stress a teacher's entertainment value or likeability or gooniese (is the teacher a soft touch grading wise). So, though I believe that student input can be useful, I think that it likely plays too large a role given that it is probably a pretty poor indicator of teaching quality.  However, it also seems that there is now evidence that it is also gender biased, and pretty severely. This piece discusses the latter. Again, the discussion is in the context of economics, but I doubt that on this matter we are much different, though I would love to be disabused of this. I would love to know what you think, especially my female colleagues.

Biology and Physics

Are there physical constraints on evolution? Of course.  However, until recently we have known little about what these might be and how they might function. Part of the interest in the Evo-Devo stuff is that it suggests how it is that biological "novelties" might be proposed before the selection mechanisms begin to dispose. However, when some (e.g. Chomsky) suggest that physical constraints might play a very large story in accounts of biological change, some of the biological cognoscenti tend to dismiss this out off hand as a serious scientific possibility. Thank god for physicists! Being on top of the scientific food chain, they are allowed to say anything they want and be taken seriously. 

Apparently one of the things they are currently investigating are the possibly severe physical constraints on evolution (here). The hero of this little linked to piece in Quanta is Jeremy England. He is at MIT and is considering the possibility that a lot of what we think of as evolution follows as a matter of natural physical law (thermodynamics in particular). In particular, life happens when energy is applied to atoms in a thermal bath. Do this and they tend to clump and form complex molecules to dissipate the energy. Do this enough and out pops life. Of course, what's interesting is that he apparently has the equations to prove this. Moreover, as England notes, this does not invalidate Darwinian thinking, rather it treats it "as a special case of a more general phenomenon," a thermodynamic one. 

From my point of view, an interesting feature of this short piece is that nobody is calling England names. Even those that are skeptical, think that it is a hypothesis worth considering and that it will generate lots of good work regardless of whether it is true or false. In other words, his speculations (and calculations) are treated as quite reasonable and maybe even true. 

The minimalistically inclined looking for examples of third factor explanations, might enjoy the discussion. At the very least, it shows that there is lots of very interesting work concerning the causal factors behind evolution. So when someone tells you (e.g. Evans most recently) that FL could not have evolved because the scenarios are incompatible with some (mis)understanding of Darwinian processes, recall that what these processes are and how they operate is currently a topic of lots of contentious and interesting new work (i.e. the scolds don't have the foggiest idea what they are talking about). 

A panel of experts debunks Evans

Ok, some hyperbole here. But I wanted to get your attention. As I mentioned at the end of the this post, linguists need to go after this junk as a public service, both to ourselves and to the larger public interested in research on language. To this end, Ewan Dunbar, Dave Kush, David Adger and moi have started putting together meatier rejoinders to Evans' confused and deeply misleading paper and book. We posted it on Reddit (here). Direct those interested to this discussion. We want to sink this before it gains traction. Feel free to point out other lapses in logic and non-sequiturs and add them to the feed. Oh yes, we gave the thing a catchy title that, we hope, leaves little room for doubt about how bad this work is.

Wednesday, December 17, 2014

Vacation!!!

Just a note to say that things will be thin for the next several weeks, at least contributions to FoL from yours truly. I am off until the start of January eating to excess, drinking profligately and generating consuming whatever is near to hand. Hope all of you have an equally rewarding break. See you in the new year.

Burgess on Tarski on truth

One of Jerry Fodor’s great lines is that you know you’re getting older when cyclic theories of history start making perfect sense. This Ecclesiastical (viz. there is nothing new under the sun) sensibility can be quite attractive to the mindset of the older academic (e.g. moi) for it provides an excellent excuse (e.g. it’s just rehashed X) to stop reading the current literature, which, truth be told, is an exhausting thing to do. However, every now and then a nice thing happens. Something is thrust in your way that you should have known about but didn’t. My non-academic self “discovered” Trollope and Dvorak and Callas in this way (and more recently I’ve gotten similarly hooked on Tana French novels). What makes this invigorating is that all of a sudden you get access to a whole lot of new good stuff that is exciting and amusing due to its freshness and that you had no idea even existed. And every now and then it even happens in the academic part of your life. In fact, this happened to me a couple of weeks ago. “Pray tell”, you say. “How? Spill!”

A month or so ago John Burgess (JB) came to campus to give a talk. Though I may have heard of this guy (and I’m not even sure of that) I am pretty sure that I had never read anything he wrote. But to get ready for the talk (I was also invited out to supper with him) I asked Alexander Williams (a dept colleague who studied with Burgess) what I should read of his to get acquainted with his work.  Alexander pointed me to this and I am forever in his debt for doing so (though don’t think you will ever collect Mr. Williams, I am notoriously bad at repayment). The essays are delicious: funny, informative, wry, insightful and just plain charming to read. Burgess in person is equally so, but I suspect that it’s easier to meet him in print than in person. At any rate, the essays were great fun to read and one in particular got me thinking about the sorts of theoretical issues that linguistic semanticists prefer to tackle mainly by avoidance. One particular question stood out: what’s the role of truth in a theory of meaning?  More particularly, what role does truth play in Tarski’s semantic theory? Burgess has a nice historical discussion of this entitled “Tarski’s Tort.”

Note that it’s ‘tort’ (as in between a felony and a misdemeanor), not ‘torte’ as in cakish pie.  At any rate, the essay discusses the kinds of confusions Tarski’s “semantic conception of truth” has wrought. In JB’s opinion, Tarski’s use of the term ‘semantic’ has caused nothing but trouble, and some of it serious.  Why? Well as JB puts it (156):

…there can hardly be any question that what “semantics” conveyed and conveys to the mind of the general theory is a theory of meaning, which Tarski’s theory most emphatically was not.

JB reviews some of the problems this terminological misstep has had for philosophical logic as well as for linguistic semantics via Davidsonianism. A little précis of the history he reviews can give you a taste of what he has in mind.

According to JB, Tarski could care less about truth. Indeed, he thought the naïve notion hopelessly confused and unredeemable. Why? Because it was beset by paradox. In other words, he thought that the standard notion was unfixably inconsistent. What he wanted was a substitute for that notion that could be serviceable for mathematical ends. As JB puts it, what Tarski sought was (167):

A restricted replacement for it [i.e. Truth, NH]: a serviceable substitute applicable not to all languages, but only to languages of a certain comparatively simple sort.

In fact, as JB outlines, Tarski used the notion of meaning to provide a local substitute for the hopelessly confused notion of truth. Or, he presupposed that we knew the meanings of certain terms to allow an extensionally adequate and precise limited definition of truth. How so?

JB again (154):

…in Tarski’s original set-up, the ‘object language” for which truth is being defined is contained in the metalanguage on which the proof is being given…In order to understand the definitions, one must understand the metalanguage, and that includes understanding the object language which is part of it, and therewith each of the words or symbols of the object language.

For example, Tarski did not (and could not) intend the various clauses of his theory to provide meanings for the words and symbols. Thus a clause that says “(A and B) is true iff A is true and B is true” cannot define what ‘and’ means as such a definition would be circular given the use of ‘and’ on the right hand side of the bi-conditional. Similarly in “(A/\B) is true iff A is true and B is true” we understand ‘/\’ in terms of understanding the meaning of ‘and.’ None of this improves when we start using model theory “talk” to set-up the relevant notions (see 163ff for discussion).

JB identifies two “syllogisms” (one ontotlogical, one semantic) that he argues are simply illegitimate, though commonly employed. These are outlined in the inferences from (1)-(3) and (4)-(6):

(1)  It’s there in the model
(2)  So it’s there in the semantics
(3)  So it’s there in the meaning

(4) These sentences have models
(5) These sentences have a semantics
(6) These sentences have a meaning

As JB puts it: “…it is one thing to have a theory of models and another thing to have a theory of meaning” (160). By themselves, giving a model theoretic semantics “does nothing towards establishing the coherence and intelligibility of any underlying motivating ideas or intended intuitive interpretation” (161).

Why is this worth noting? Well because of the role that truth plays in contemporary theories of meaning. JB observes that Davidsonians (and most other contemporary semanticists so far as I can tell)[1] in pursuing truth conditional theories of meaning (TCTM) have stood Tarski “on his head” (162). As JB puts it on (166):

…[Davidsonians, NH] make what for Tarski were clauses in a definition of truth in terms of already understood notions like negation and conjunction, into definitions of a kind of those operators in terms of a notion of truth taken as primitive.

So, whereas Tarski defined a mathematically serviceable theory of truth by taking for granted an understanding of meaning, TCTM theory takes truth as basic and intends to define meaning with it, a move that Tarski, being skeptical of the viability of a general notion of truth would have been very very skeptical of. And why? Because Tarski held that the notion of truth was inconsistent (due to the problems raised by the paradoxes) and “the inconsistency theory of truth is incompatible with the truth conditional theory of meaning” (167).

Paul Pietroski has discussed the consequences of some of this for current semantic theory (see here and here). The upshot is that the paradoxes constitute a serious theoretical problem for TCTMs.  This does not mean that all work done assuming TCTM must be cast to the flames. But it does mean that there exists an important theoretical task of either defending the TCTM against the problems the paradoxes raise or seeing how the results obtained using a TCTM can be reinterpreted in less conceptually fraught terms.  Having read JB, I am pretty sure that were Tarski asked, he would have endorsed the second kind of re-analytic project, given his jaundiced views concerning the viability of a coherent general conception of truth.[2]

Linguistic semanticists have been, by and large, uninterested in foundational issues. From where I sit, this is because semanticists have mainly been interested in describing (or “capturing”) the semantic facts.  The aim has been to put into formal terms “semantic” facts. There is nothing wrong with this. Indeed, there is a lot that is right on. It is analogous to what syntactitians spent most of their time doing in the 60s (i.e. establishing a body of analyses that hopefully would provide fuel for more serious theoretical speculation). However, even more than in syntax, it is tempting to confuse formal work with theoretical work, especially given the awesome mathematical “look” of the proposals.  But, to reiterate a point JB makes repeatedly, the two are very different.

For whatever reasons, linguists have shied away from investigating the theoretical core. Maybe, having been reassured by philosophers that recursive truth theories were conceptually ok and given a kind of Davidsonian (and also Lewis, and Montague, etc.) seal of approval, we have assumed that there is nothing foundationally suspect with truth as a basic interpretive notion. But, this assumption is, and always was, very very controversial, and qua theorists (even if not as descriptivists) we ought to worry about these foundational notions.[3]

To end: Burgess writes great papers. The one on Tarski and TCTMs is one of many in his book of essays. Aside from being entertained (and I mean lol kinds of moments), the points raised are also edifying and present plenty for the theoretically minded linguist interested in meaning to chew over.  








[1] With the conspicuous exception of Paul Pietroski (see here), I believe.
[2] JB noting some work by Kripke on the topic suggests that things are pretty much where Tarski left matters wrt getting a more coherent general conception. See p. 167.
[3] Before ending, let me point to one other paper worth looking at, Hartry Field’s old paper on Tarski’s theory of truth (here). Field outlines a project for a conceptually respectable theory of truth that focuses on scientifically understanding (i.e. conceptually and theoretically grounding) another semantic notion, primitive denotation.

Friday, December 12, 2014

Learning?

Consider this nice little video on pygmy sea horses. They apparently match their color to the coral that they land in. So off-spring of orange sea horses go purple when placed on purple coral. So there is a general capacity to change colors and a specific capacity to match the color one is exposed to. Is this learning? It is environmentally responsive, right? But does one really want to say that the Color Acquisition Device "learns" which color to become?

I am sure that you can see why I am asking this.  Language from where I sit looks a lot like this: G development in response to environmental input. The two cases are not identical, but they are not entirely different either.  At any rate, enjoy the video. These critters are cool.