Wednesday, January 28, 2009

Meeting 4: Functions (2/4)

Required Readings:
  • Godfrey-Smith, "Functions: Consensus without Unity" [PDF]
  • Neander, "Functions as Selected Effects: The Conceptual Analyst's Defense" [PDF]
  • Davies, "The Nature of Natural Norms: Why Selected Functions are Systemic Capacity Functions" [PDF]
The function of a heart is to pump blood. Some hearts are defective in this regard: they don’t do what they are supposed to do. We can explain why Smith died on the basis of this sort of malfunction. But it isn’t quite clear how malfunctions make sense in a modern conception of biology. Compare the functions of artifacts. My fridge has the function of keeping things cold (when it fails to, we say that it is malfunctioning). We make sense of this by citing the design of refrigerators: their function is to keep things cold insofar as that was the purpose for which they are built — someone had the intention of building a device that would keep things cold. Note how this explains why we do not ascribe the function of making a subtle humming noise to refrigerators: that wasn’t the purpose for which they were built.

The difficulty in biology should now be apparent. If evolutionary theory excises any need for purposes (Aristotelian Final Causes) or intentional design, how can we then attribute function in any normative sense to biological objects? Two answers (or styles of answers) have dominated the literature: etiological (or selected effect) accounts and systemic capacity accounts. The first is represented by Neander’s paper (but was first proposed by Larry Wright) and takes questions about functions as questions about the explanation of a thing’s existence. To ask what the function of the human heart is, on this account, is to ask in virtue of doing what is the heart possessed by humans. It’s in virtue of the pumping action of hearts (and not, say, the pumping noises they make) that their possessors have prospered. So natural selection, on this view, gives us the sense of normativity which we pretheoretically attribute to (proper) functions.

Not everyone is convinced by this general account. Lots of questions arise here. Is the etiological theory a general account of function (Wright’s version appears to be) or is it only applicable in the biological world? Is it meant as a conceptual analysis of the notion of function? Does it suppose that traits evolved carrying out the function that they now have — can the etiologist make sense of Gould and Vrba’s exaptations? Partly in response to difficulties like these, many philosophers have turned to a more liberal causal role (or systemic capacity) account of function which abjures reference to history (selective or otherwise) in favor of what Cummins called functional analysis. On this systemic capacity view, a trait’s function(s) are just whatever causal capacities that trait contributes to a system. On this view, the “normativity” of function wanes, as the number of distinct functions skyrockets. We may still be able to make sense of the function of the heart to pump blood and not make pumping sounds, in virtue of the fact that the former (but not the latter) activity contributes to the performance of the system in which hearts are embedded.

Davies defends this systemic capacity approach, arguing that it actually subsumes the etiological approach. For an excellent (obviously opinionated) background on the different theories and how they compare, you might consider reading his essay first and then circling back to Neander’s.

Study Questions
  • Godfrey-Smith proposes that we should understand functions as effects that have led to a trait's being preserved or proliferated through recent episodes of natural selection. Does this effectively deal with the difficulties facing the etiological approach?
  • Describe some prima facie differences in the explanatory aims between the systemic capacity account of functions and the selected effect account.
  • Neander mentions three objections to the etiological theory of proper functions. Briefly describe them.
  • Neander writes that it is “indeed the vague, unifying, everyday notion of a ‘proper function’ from which the biological notion is derived. Nonetheless, the peculiarities of natural selection impose certain constraints upon a more detailed and precise analysis of the biological notion, . . . constraints which do not apply to the everyday notion employed by artifacts” (175). How does this fit in with her take on the role of conceptual analysis in contrast to theoretical definition.
  • What do you think of Neander’s response to the “intellectual arrogance” objection?
  • How does Neander propose to deal with the “instant winged lions”? Do you find this a satisfactory response to the problem?
  • Briefly describe Neander’s cancer objection to the causal role theory. Does Davies have a credible response?
  • What is Davies’ argument that systemic capacity functions have a broader range of application than do selected functions? Does it seem sound?
  • Does Davies believe that there are selected functions?
  • Why does Davies object to natural norms?
  • Why does Godfrey-Smith think that Kitcher is wrong to seek unity in different accounts of function?

Assignment 3 (due 2/4)

Neander discusses three objections to the selected effects view of functions. Choose one to discuss. Carefully explain what the objection is and critically discuss how Neander purports to solve it.

Wednesday, January 21, 2009

Assignment 2 (due on 1/28)

Pick three of the study questions for Meeting 3 to answer in no more than one sheet total (it may be double-sided).

Best . . . Simpson's . . . "Couch Gag" . . . ever!

See more funny videos at CollegeHumor

Meeting 3: Sociobiology & Evolutionary Psychology (1/28)

Required Readings:
  • Tooby and Cosmides, "Toward Mapping the Evolved Functional Organization of Mind and Brain" [CIEB §9]
  • Buller, "Evolutionary Psychology: A Critique" [CIEB §10]
  • Haufe, "Perverse Engineering" [PDF]
  • S&D, Chapters 13-14 **
If we are indeed products of evolution, then doesn’t it stand to reason that our evolutionary past can tell us something about ourselves now (as well as our futures)? This was the basic premise of the “sociobiologists” in the mid-70s and the “evolutionary psychologists” prevalent now. But sociobiology was a controversial theory (or framework) right from the start. Critics smelled genetic determinism, bad adaptationist thinking, sloppy argument, weak empirical support, and so on.

Evolutionary psychology billed itself as the grown-up, fixed-up, and focused version of essentially the same program: integrating evolutionary biology with human psychology. One of the central battlegrounds of this debate concerns our cognitive architecture: is the mind a sort of all-purpose, plastic computer or is it (as many influential evolutionary psychologists suppose) a conglomeration of domain-specific modules? If the latter, presumably, our evolutionary history as foraging primates ought to shed some light on certain features of our psychology now. After all, recorded history represents a rather small portion of hominid history.

I am extremely skeptical about much of evolutionary psychology. So are Buller and Haufe. As you probably know, skepticism is ambiguous: it can mean either disbelief or suspension of belief. Both seem appropriate. Some of the empirical claims of evolutionary psychologists seem to be false; other claims simply lack adequate support. And yet, there is something undeniably attractive about evolutionary psychology as a general strategy, as perhaps, there is with certain forms of adaptationism. The challenge, then, would seem to be how to separate the wheat from the chaff. What if anything can our evolutionary history tell us about ourselves?

Study Questions
  • What concerns about sociobiology (as described in the *optional* S&D reading) seem to you most pressing? What about for evolutionary psychology?
  • What do you think of Tooby and Cosmides’ claim that the human brain is adapted to the hunting-gathering lifestyle of our Pleistocene forebears?
  • Tooby and Cosmides claim that understanding human neural architecture is “a problem in reverse engineering” (184). What, specifically, does this entail?
  • Haufe claims that the method of reverse engineering (RE) in evolutionary biology faces some deep conceptual difficulties. What are these difficulties? What empirical difficulties does RE face?
  • What are the experiments with the Watson selection task supposed to show about the "modularity" of the mind? Why does Buller believe that they fail to show this?
  • Evolutionary psychologists have argued that domain-general cognitive mechanisms, insofar as they are (or would have been) maladaptive, are impossible. Why is this claim false?
  • It has been alleged that evolutionary psychology (like sociobiology) involves a heavy does of adaptationism. What kind(s) of adaptationism would you suppose this to be and why?
  • What significance does the possibility of genetic drift have in discussions of evolutionary psychology?

Tuesday, January 20, 2009

Toxic Newts!

I came across this video (from a PBS program) a while ago that presents a lovely example of how "evolutionary arms races" can produce dramatic adaptations. Fun stuff!

Thursday, January 15, 2009

Course Requirements & Policies

Now you can recycle your paper syllabi. This post will be your reference for how I will assess your learning in this course.

Attendance & Participation (10%). This should be obvious: you should come to every class meeting (especially for a one-a-week class). After one missed class, each further unexcused absence will reduce your final grade by three percentage points; more than four unexcused absences will mean an automatic failure (you can’t miss a whole quarter of the course and expect to pass — this is not a “skills course”). If you must miss a class (and I’ll be the judge of ‘must’), you should contact me before the class in question (unless circumstances make this impossible for some strange reason — I’ll be the judge of ‘impossible’ as well); missed presentations will be scored a zero and will not be dropped (see below). Earning an ‘A’ for this section of the course will require being an involved and helpful participant (raising questions and engaging in the discussion without dominating it) in the vast majority of our meetings. Simply attending and at looking attentive will get you at most a ‘C’ for participation.

Weekly Assignments (15%). Each week, you will write one sheet in response to a question (or a series of questions) concerning the reading. These will be due at the beginning of class and be evaluated on a 0–4 scale (0=“not done”/“wildly insufficient”, 1=“needs improvement”, 2=“acceptable”, 3=“good”, 4=“excellent!”). While no extensions will be granted for any reason (“legitimate” or otherwise), I will drop your lowest three marks. At the end of the course, I will sum your remaining scores and curve the result so that an average of ‘3’ comes out to a B+.

Impromptu Presentations (20%). Unless you are giving a formal presentation in a certain class (see below), you will be on call to give a short, “impromptu” presentation on a topic of my choosing (generally selected from the study questions I make available on the website or from the weekly reaction paper topic). These will be random. I have a 20-sided die, you’ll each get a number. If your number gets rolled, you’ll speak to us for five or so minutes. I’ll let you punt twice (i.e., you can say, “um, I’d rather not do one of these now” without penalty — but only if you’re there to say it!). These will be scored on that 0–4 scale; I’ll drop the worst non-zero score, and average together the rest and curve the result around a B+.

Short Essay (15%). A short essay (1,500–2,000 words for undergraduates, 2,000–3,000 words for graduates) is due by March 11th at 3:30PM. I will not assign paper topics (though I can give you some suggestions if you’re stuck). Instead, I invite you to write on (subject to my approval) whatever you’re finding most interesting in the course and turn it in whenever you have the opportunity. What’s more, you may submit multiple essays (up to one per week, including at most one rewrite of the same essay) and only your best will count toward this grade category. Since you have all the time in the world to adjust your schedules, late essays will be dealt with rather harshly: late essays will be docked five percentage points per partial day late — e.g., you get a 82% on an essay submitted one hour late; it receives a 77%).

Formal Presentation (10%) & Response (5%). Toward the second half of the term, we will start doing formal in-class presentations of the sort that one would see in a professional academic conference. You will be presenting an original research paper on a topic in the neighborhood of the topic scheduled for class that day. These presentations will run from 10–15 minutes and will be based on a 1,500–2,000 word essay. Each presentation will be assigned a commentator who will offer a five minute commentary after which the speaker will be permitted a brief reply. At this point, we will open up the discussion to the group. You should start thinking early about when you’d like to present and when you’d be willing to comment. Commentators and I should receive the paper by the weekend before the presentation is scheduled.

Final Essay (25%). Your final essay (2,000–3,000 words for undergraduates, 3,000–5,000 words for graduates) will be based on your presentation and should incorporate the feedback you receive on that occasion. These will be due by May 11th at 3:30PM.

I have high expectations of you: that you read everything carefully, that you actively engage with the discussion, that you stringently observe a no-bullshit-policy, and that you complete work on time. But you should have high expectations of me as well. I am very often available outside of class to help you understand course material. I’m happy to read drafts, discuss questions/issues, and help you sort out your thoughts as best I can. If I’m in my office and distractable (as I often am), I’ll try to set my IM status to “Available” (my IM handle is ‘mslater@uidaho.edu’)

Texts:
Sober (Ed.), Conceptual Issues in Evolutionary Biology, 3rd Ed. (MIT, 2006)
Lewontin, The Triple Helix (Harvard, 2000)

Other articles provided in PDF format on the Blackboard website.
The interests of trees and our learning sometimes conflict. Please do what you can to minimize paper waste (use recycled paper, reclaimed paper, &c.; printing the articles two-up, double-sided in Acrobat is usually possible), but please bring copies of the relevant articles to our meetings (on a laptop is fine), as we will often need to read them closely together.

Optional Text: Griffiths and Sterelny, Sex and Death (UChicago, 1999)
This book (referred to as ‘S&D’ in the schedule) is a fairly comprehensive introduction to the philosophy of biology. Several of its chapters provide useful background to the issues we’ll be dealing with; many chapters take on different topics that we won’t get to. If you’re interested in reading more in the philosophy of biology, it’s a great book to have on your shelf.

Wednesday, January 14, 2009

Meeting 2: Fitness and Adaptation (1/21)

Required Readings: (I recommend going in this order). Remember that starred items are required for grad students, but optional for undergrads; and double-starred items are optional for everyone and that 'CIEB' denotes the Sober collection Conceptual Issues in Evolutionary Biology.
  • Mills & Beatty, “The Propensity Interpretation of Fitness” [CIEB §1]
  • Sober, “The Two Faces of Fitness” [CIEB §2] **
  • Gould & Lewontin, “The Spandrels of San Marco and the Panglossian Paradigm” [CIEB §5]
  • Gould & Vrba, “Exaptation: a Missing Term in the Science of Form” [PDF]
  • Dennett, “The Leibnizian Paradigm” [PDF] *
  • S&D: Chapter 10: “Adaptation, Perfection, Function” **

We'll address two important issues for the interpretation of evolutionary biology this week: the status of Darwinian claims about fitness (captured in such well-known slogans as "the survival of the fittest") and the concept of adaptation and adaptationist thinking.

As I mentioned today, Karl Popper was deeply influential in the philosophy of science through much of the 20th century. His criterion of science — "falsifiability" — stipulated that in order for a theory to be judged as "scientific", a theory must be subjected to "severe tests". There must be experiments you could run or observations you could make that would show the theory to be false. That's a bad criterion of science for several reasons. Suffice it to say, that many perfectly legitimate theories have not been cast away on the basis of a surprising observation. As Kuhn put it, it's a bad carpenter who blames his tools. I might say more about this next time.

Nevertheless, the idea that science should be falsifiable continues to exert a great deal of influence. Perhaps there's some good reason for this. Unfalsifiability may bespeak other theoretical vices, like circularity. This is roughly the charge Mills and Beatty are concerned to rebut in their article on fitness. As we know, differential fitness is required for natural selection to drive evolution. But what is fitness? How is it defined? Not by "burliness" or "speed" or even being adapted to some environment. What matters is reproduction. It's tempting to understand fitness as a measure of how many descendants an individual leaves behind. But then it's no surprise that the fittest survive to reproduce: for fitness is defined as survival to reproduce! Thus, Darwin's theory is circular and not truly scientific. The basic idea behind Mills and Beatty's approach is that 'fitness' in evolutionary theory can be understood in at least two different ways: fitness of an organism and fitness of a type, and that we should construe each of these claims as claims about propensities to reproduce, rather than actual reproductive performance. (Don't worry about trying to understand the example on p. 16 of CIEB in detail — I'll run through it.)

Another source of concern about Darwin's theory is that it is merely a series of promissory notes — that it doesn't actually explain anything, but merely suggests that some evolutionary story or other is tellable. Kitcher effectively responds to this general charge in connection to the falsifiability concern in his "Darwin's Achievement" (which is certainly worth a look if you have the time). But there remains an influential strand of evolutionary thinking which Stephen Jay Gould and Richard Lewontin famously dubbed "The Adaptationist Program" and lampooned in the spirit of Voltaire: that any trait can be explained by being adaptive (by contributing to the fitness of the organisms which possess it). The ability to tell some unfalsifiable "just-so" story doesn't really explain anything! One of the interesting issues here is whether Gould and Lewontin go too far in their rejection of adaptationist thinking: whether there isn't something to adaptationist thinking.

Dennett thinks so. He offers a refreshingly frank admission of his longing to believe evolutionary stories involving avian honey guides and aquatic apes. . . . Is he just offering an optimistic counterpoint to Gould and Lewontin? Perhaps since, as Dobzhansky put it "nothing in biology makes sense except in the light of evolution", some evolutionary story or other has to be behind various adaptations we shouldn't be too worried about indulging in adaptationist reasoning. The Dennett vs. Gould/Lewontin debate is something we should talk a bit about.

Gould and Elisabeth Vrba, a few years after Gould and Lewontin wrote their influential critique of adaptationism, offered an important concept that illustrates a worry with Dennett's optimistic approach. Because some trait is adaptive does not necessarily mean that its prevalence owes to its having been adaptive in that way (this distinction will loom large in our discussion of biological function in a few weeks). Feathers may be a good example: did they arise and proliferate because they were good for flying or because they were good for other things and then get co-opted for flight? Gould and Vrba want to call this an "exaptation".

Study Questions
  • You might think about these questions as plausible targets for your impromptu presentations.
  • What is a propensity?
  • What is the difference between fitness as actual reproductive success and fitness as a “propensity”?
  • Explain how understanding fitness as a propensity relieves the circularity problem discussed in Mills and Beatty.
  • Mills and Beatty distinguish between the fitness of individual organisms and the fitness of types. What is the difference? Why do they write that fitness of types cannot be a propensity?
  • What is an adaptation?
  • What is the adaptationist program according to Gould and Lewontin? What’s wrong with it (according to them)?
  • What challenges do the adaptationists face in dividing organisms up into traits (according to Gould and Lewontin)?
  • Why think that the adaptationist program is unfalsifiable?
  • What is “exaptation”?
  • What is a “Bauplan”? How does it fit into the debate about adaptationism?

Assignment 1 (due 2/21)

Please write no more than one sheet (two-sides if you must) in response to the following questions. Be succinct but complete. Strive for clarity and detail, keeping your prose as simple as possible.

1) What, precisely, is the circularity worry that many believe Darwin's theory faces? Summarize it and how Mills and Beatty purport to solve it.

2) Describe the difference between 'adaptation' and 'exaptation'.

Thursday, January 8, 2009

Meeting 1: Introduction

First meetings of courses are often short, trivial occasions. I see no reason why ours must be. We'll begin by discussing the structure of Darwin's theory, its origin and subsequent elaboration in the context of improved genetic knowledge, and how it has been confirmed to such a dramatic extent. This will put us in a position to begin to address the conceptual questions about evolutionary biology which will detain us for the bulk of the course.

I hope you'll have a chance to read some of the following as background to our discussion. To access these, you will need to log in to Blackboard (if you're registered in the course, you should have access to the blackboard page now --- or you will shortly). If you have not yet registered or are a WSU student, please send me an email and I'll send you a link from which you can download them.

Optional/Recommended Reading:
  • Mayr, chapter 2 and chapter 6 of One Long Argument
  • Kitcher, "Darwin's Achievement"
  • Ridley, chapter 4 of Evolution: this chapter on variation and natural selection may be useful reading for those who feel a bit shaky about their biological background.
See you in class on Wednesday the 14th!