Tuesday, February 28, 2012

Cohen and Dennett on Reportability and Consciousness

I was struck by the following imaginary dialogue in a recent article by Michael Cohen and Daniel Dennett. In the dialogue, P is a patient and F&L are Fahrenfort and Lamme, the targets of C&D's critique.

F&L: ‘You are conscious of the redness of the apple.’

P: ‘I am? I don’t see any color. It just looks grey. Why do you think I’m consciously experiencing red?’

F&L: ‘Because we can detect recurrent processing in color areas in your visual cortex.’

P: ‘But I really don’t see any color. I see the apple, but nothing colored. Yet you still insist that I am conscious of the color red?’

F&L: ‘Yes, because local recurrency correlates with conscious awareness.’

P: ‘Doesn’t it mean something that I am telling you I’m not experiencing red at all? Doesn’t that suggest local recurrency itself isn’t sufficient for conscious awareness?’
I think we are meant to find F&L's insistence preposterous, or at least misguided.

Is it preposterous or misguided? I feel the attraction of saying so. But imagine this parallel case, in which the patient's report is of a visually seen object and the scientists are speaking to the patient from another room in the building:
Scientists: ‘You are looking directly at an apple that is on the table two feet in front of you.’

Participant: ‘I am? I don’t see an apple. It just looks like an empty table. Why do you think I’m looking at an apple?’

S: ‘Because we put the apple there, and we are monitoring it with a suite of video cameras and other devices [fill in further convincing details].’

P: ‘But I really don’t see an apple. I see the table, but no apple on it. Yet you still insist that there's an apple there?’

S: ‘Yes, because [repeat suite of persuasive empirical evidence].’

P: ‘Doesn’t it mean something that I am telling you I’m not seeing the apple? Doesn’t that suggest that your video cameras, etc., are broken?’
[Update, Mar. 16: Just to be clear: The dispute I am imagining is not about P's mental life. It's about the fact of whether there is actually an apple on the table.]

Here's my thought: This is a fairly bizarre situation. One wonders if the scientists' cameras are broken after all. But whether to believe the scientists or the participant is going to depend on further details. How trustworthy is the scientists' equipment? Is there some plausible reason to think the participant might really be mistaken? For example, what if the participant had been given a post-hypnotic suggestion? What if the participant were viewing the apple monocularly and the apple were being manipulated so as to remain always in the participant's blind spot? Then we might have excellent reason to believe the scientists over the participant.

I would suggest that the introspective case is epistemically similar. It doesn't hands-down favor the patient. It depends on the details. It depends on such things as the trustworthiness of the external measure of consciousness and whether a reasonable explanation of the patient's error is available. We should not, contra Cohen's and Dennett's apparent intention, conclude from this thought experiment that self-reports of experience are in any strong sense "incorrigible".

(Dennett and I have already gone around a few times on this issue: here and here and here.)

Update, March 13:
Cohen and Dennett have given me permission to post the following reply on their behalf:

Thanks to everyone for the comments! Here are just a few points of clarification of our view.

For us, the subject's words are not the ultimate criterion or touchstone of consciousness. Not at all! Change blindness and inattentional blindness and many other phenomena demonstrate how people often overestimate their knowledge of their own experiences. But if we want to understand everyday subjective experience—and that is what people have in mind generally when they speak of consciousness—we have to start with the understanding that in general people have access to their own experience! But theorists like Block, Lamme, and colleagues want to go a step beyond that. They want to say that there are conscious experiences that you can't even access yourself. In other words, there are experiences that you can't talk about, you can't report, you can't remember, you can't make decisions about, you can't plan to act in one way or another because of, and even if you're directly probed, you will still not realize you're having it. (This is what Block and Lamme mean when they insist that there can be phenomenal consciousness without access consciousness. (See Lamme, 2003 TICS where he talks about conscious states you can't access or realize you're having).

We do not at all deny that there are instances in which a scientist can make observations about a subject's neural state that the subject can't report. There are too many instances in the scientific literature to list here. For example, it's easy with current technology to measure fluctuations in primary visual cortex (V1) using fMRI to which the subject has no access. Not only can he not report the change in his V1, he can't even recognize something on the screen is changing that is causing those neural changes. The idea that subjective report is the only tool we have for consciousness studies is not at all our view. Our view is that there are two quite well established categories: conscious experiences to which subjects have access, and unconscious processes to which they do not have access. If Block and Lamme want to propose a new category of phenomenal consciousness with no access, they must motivate it. How are they proposing to distinguish it from unconscious activity? In virtue of what properties are the phenomena at issue rightly called conscious? Freud proposed a similar distinction, between totally unconscious and “preconscious” activities, and more recently Dehaene et al (TICS 2006) have updated that proposal with a carefully defended taxonomy of sublimininal, preconscious and conscious activity. Are Block and Lamme proposing to simply rename Dehaene et al’s ‘preconscious’ category as phenomenal consciousness? If so, what don’t they like about the term ‘preconscious’? If not, if they want their taxonomy to compete with this taxonomy, they need to tell us what special features mark the phenomenally conscious but unaccessed activities from Dehaene et al’s preconscious activities.

[For a few of my (ES's) thoughts in reaction, see the comments section, March 13.]

Monday, February 27, 2012

Experimental Philosophy Institute 2012

Faculty who want NEH to pay for them to spend this July in Tucson studying experimental philosophy with some of the top experimental philosophers should check this out.

Tucson in July? I told you x-phi is hot!

New Blog on the Philosophy of Cosmology

... here. Over the last few years, I've found my thoughts about the epistemology of metaphysics leading me more toward the philosophy of cosmology (e.g., my "Crazyism" essay, section xii here, and my reflections on solipsism on the the Sims argument.) So it's nice to see the philosophy of cosmology project starting to take off.

Sunday, February 26, 2012

Faux Philosophy News

... humorous philosophy blog, off to a hilarious start.

Friday, February 17, 2012

4th Online Consciousness Conference

has begun and will run through March 2nd. Check it out!

Why Dretske Should Think That the United States Is Conscious

Last week, I argued that Daniel Dennett should think that the United States is conscious. That is, I argued that Dennett should think that the United States has a stream of experience in the same sense that you and I have streams of experience, or in other words that "there's something it's like" to be the United States. Today, I'll say the same about Fred Dretske. As I mentioned in discussing Dennett, these reflections aren't intended as refutations of their views. I think we should seriously consider the possibility that the United States is literally conscious.

Dretske presents what is perhaps the leading philosophical account of the nature of representation, and he also offers one of the leading representationalist theories of consciousness. Dretske and Dennett offer perhaps the two most prominent top-to-bottom materialistic philosophical accounts of the metaphysics of consciousness, which is why I have chosen them for this exercise.

Let's start with representation. On Dretske's view, a system represents that x is F just in case that system has a subsystem with the function of entering state A only if x is F and that subsystem is in state A. Dretske's examples of systems with indicator functions include both artificial systems like fuel gauges and natural biological systems.

So we need to think a little bit about what a "system" is. Intuitive application of the label "system" wouldn't seem to exclude the United States. We can think of a traffic system or a social system or the military-industrial complex as a system. Systems, I'd be inclined to think, can be spatially distributed, as long as there is some sort of regular, predictable interaction among their parts. There seems to be no reason, on Dretske's view, not to treat the United States as a system. Dretske does not appear to employ restrictive criteria, such as a requirement of spatial contiguity, on what qualifies as a system. In fact, it would strain against the general spirit of Dretske's view to employ something like spatial contiguity as a criterion of systemhood: Something like a fuel gauge could easily operate via radio communication among its parts and that would make no difference to Dretske's basic analysis. What matters for Dretske are things like information and causation, not adjacency of parts.

If the United States is a system, then it can presumably at least be evaluated for the presence or absence of representations. And once it is evaluated in this way it seems clear that, by Dretske's criteria, the United States does in fact possess representations. The United States has subsystems with indicator functions. The Census Bureau is part of the United States and one of its functions is to tally up the residents. The CIA is part of the United States and one of its functions is to track the location of enemies.

Dretske is very liberal in granting "behavior" to systems: Even plants behave, on his view (e.g., by growing), and in some sense even stones (e.g., by sinking when thrown in a pond). So it seems clear if we grant that the United States is a system with representations, it also exhibits behavior that is influenced by those representations. Dretske's metaphysics, straightforwardly applied, would seem to imply that the United States is a behaving, self-representing system.

But would this behaving, representing system have conscious experience, on Dretske's view? Dretske says that in order to have conscious sensory experience, a system must possess representations that are (a.) natural, (b.) systemic, and (c.) enable the construction of new representations that can be calibrated to regulate behavior serving the system's needs and desires. Let's consider these criteria one at a time, b, c, and then a.

Does the U.S. have "systemic" representations? Systemic representations, per Dretske, are representations that are part of the very design of the system or subsystem, rather than representations acquired later. It seems clear that the United States has these, if it has representations at all. It's among the systemic functions of the Census Bureau that it tally up the residents. It's among the systemic functions of the Supreme Court that it represent laws as Constitutional or un-Constitutional. The systemic representations of these subsystems deliver behavior-guiding information to the system as a whole, as the systemic representations of an animal's sensory subsystems do.

Can the United States construct new representations derived from these systemic representations to further regulate its behavior? It seems clear it can. The United States, or a subsystem within the United States, could represent its rate of population growth among newly-defined demographic groups and adjust immigration policy in response. Does it do so in accord with its needs and desires? Well, needs and desires, on Dretske's account, don't require a lot of apparatus. A desire for some result R, per Dretske, is an internal state that (a.) helps cause movement that helps to yield R, (b.) was selected for because of that tendency to help yield R, and (c.) can be further modified conditionally upon its effectiveness in producing R, in a somewhat sophisticated way. Though these conditions rule out the inflexible inherited drives of many insects, this is still pretty simple stuff, as Dretske intends. The Census Bureau, the CIA, and the United States as a whole would seem to have desires by Dretske's criteria.

Finally, does the United States have "natural" representations that play the necessary roles? This might seem to be a sticking point. Dretske defines conventional representations as those arising when "a thing's informational functions are derived from the intentions and purposes of its designers, builders, and users" -- that is, "us" -- and he defines natural representations as just those that are not conventional (1995, p. 7-8). Now clearly the informational functions of the United States depend on us. They wouldn't exist without us. Does that mean, then, that Dretske can dodge the conclusion that the U.S. is conscious?

I don't think so. After all, your own informational functions depend on you, wouldn't exist without you, and you're conscious. The motivation for Dretske's requirement seems to be that to give rise to consciousness a system's representational functions should be intrinsic to it, rather than assigned from outside. When you slap a label on a column of mercury and call it a thermometer, you don't thereby make the thermometer conscious (even if it were complex enough to meet the other criteria). But the case of the thermometer and the U.S. are not at all analogous. U.S. citizens aren't external label-slappers. We are parts of the United States. We constitute it. We are internal to it. Although Dretske implicitly assumes that if a system's representational capacities depend on human beings then those capacities are not natural to the system, it's clear that in saying this he has ordinary physical artifacts in mind, not cases where human users themselves constitute (part of) the system.

The core idea of Dretske's metaphysics of mind is that minds are information-manipulating systems, where information is construed in terms of simple causes and probabilities, and where mentality and consciousness arise when a system's environmental responsiveness and its tracking of the world are intrinsically sophisticated and flexible. If we can set aside our natural prejudice against large, spatially distributed systems, it seems clear that the United States amply satisfies Dretskean criteria for conscious mentality.

Thursday, February 16, 2012

A 15-Minute Survey on Stereotypes about Philosophy

by the good folks at Sheffield, here.

Wednesday, February 15, 2012

The Surprising and Disappointing Predictors of Success in UCR's Philosophy PhD Program

Well, surprising and disappointing to me at least! You might be neither surprised or disappointed.

Here's the background: I'm on the UCR Philosophy PhD admissions committee again this year. I'm a fan of treating senior-year GPA in philosophy as a crucially important part of an application. Here's the kind of thing I tend to say to other members of the admissions committee: "For each A-minus, imagine an unwritten letter saying that this student isn't quite top notch and not really ready for a PhD program in philosophy". I'm also a fan of not putting too much weight on the reputation of students' undergrad institutions. I'm cheering for the Cal State underdogs. And the GRE I'm inclined to regard as having no predictive value once GPA, writing sample, and letters of recommendation are factored in. (I compare GRE to the bench press as a predictor of athletic performance. If you knew nothing else, it would be somewhat predictive, but once you've seen the person in the field, it really doesn't matter.)

Being an empirically-minded philosopher, though, I'm not happy with mere armchair plausibility. So I thought I could give extra weight to my arguments by looking at how current UCR grad-student performance relates to undergrad GPA, to undergrad institution of origin, and to GRE scores. The staff in the department office kindly provided me with data for all grad students from the entering class of 2007 to the present. This is only 37 students total (with some missing cells), but I thought I might at least pick up some trends. My two measures of academic success at UCR are GPA in the program (setting 3.5 as a floor because of two outliers with some Fs) and whether the student dropped out of the program.

It looks like everything I thought I knew is wrong.

I couldn't make undergrad GPA predictive. I tried several different ways. I tried including undergrad GPA for all students and I tried excluding those who had done some master's work before coming to UCR. When overall GPA didn't work I asked the staff to recode the data with just senior-year GPA in philosophy courses. Still no correlation. Maybe on a much larger sample GPA would show up as predictive, but on this sample it's not even close, not even close to close.

Two important caveats: First, all the students had excellent undergrad GPAs (except for one who repaired with a Master's degree). We're comparing 3.7's vs. 3.9's here, not 3.0's vs. 3.9's. In philosophy courses, their GPAs are even better: Median senior year philosophy GPA was 3.91. So surely this is a ceiling effect of some sort. Still, in my mind, 50% A-minuses in senior-year philosophy looks very different in a PhD application than does straight A's in senior-year philosophy. I would have thought the second sort of student much more promising overall. Second: The students with relatively lower GPA's who were nonetheless admitted (and thus the only students in this sample) presumably had especially excellent letters and writing samples, to help compensate for their disadvantage in GPA relative to other applicants. So maybe that's the explanation. (See, I just can't abandon my opinion!)

Equally annoyingly, given my biases, the verbal section of the GRE was highly predictive. (Math was not predictive.) Verbal GRE score correlates at .49 with graduate student GPA in Philosophy at UCR (p = .004). Our students' median verbal GRE score is 680. Those who scored above median have a mean UCR GPA of 3.91. Those who scored median or below have a mean UCR GPA of 3.76 (t test, p = .001). (Yes, we mostly give our PhD students grades ranging from B+ to A. If you're getting mostly A-minuses and B-pluses in our program, you're "struggling".) This shows up especially strikingly in a 2x2 split-half analysis. 11/14 (79%) of students with above-median verbal GREs have above-median GPAs in our program, while only 5/18 (28%) of students with at-or-below-median verbal GREs have above-median GPAs in our program (chi-square, p = .004).

There was also a trend for overall GRE score to predict sticking with the program: Dropouts had a mean GRE of 1243. Non-dropouts had a mean GRE of 1385. (This was not statistically significant, partly because the dropout group had much higher GRE variance, messing up straightforward application of the t test; p = .13, p = .01 assuming equal variances.)

And reputation of undergrad institution was predictive of GPA in our program. Students whose undergrad institution is a US News top-50 National University or top-25 National Liberal Arts College had a mean 3.91 GPA at UCR, while those not from those elite institutions had a mean GPA of 3.77 (t test, p = .01, equal variance not assumed).

The one bright spot for my preconceptions was this: Students with graduate-level training (usually an MA) before entering UCR tended to do well in the program. Their GPA was 3.87, compared to 3.77 for students with no prior graduate-level training (t test, p = .06); and they were much less likely to drop out: 1/18 (6%) vs. 8/19 (42%) (chi-square, p = .01).

I'm tempted to claim the philosopher's prerogative of rejecting empirical evidence I don't like and sticking with my armchair intuitions. Surely there's something in Kant I can use to prove a priori from principles of pure reason that undergrad GPA is more important than GRE! One thought is this: Since we don't take GRE very seriously in admissions and we do take undergrad GPA very seriously, whatever predictiveness GRE has isn't washed out through the admissions process in the way that the predictive value of GPA probably is to some extent washed out (per caveat 2 in the GPA discussion). If we started taking GRE very seriously in admissions, its predictive value among admitted students might vanish, since those with low GREs would have to be all the more excellent in the other dimensions of their application.

I'd be interested to hear if other professors at PhD have similar data, and whether they find similar results.

Thursday, February 09, 2012

Why Dennett Should Think That the United States Is Conscious

If you're reading this, you probably know who Dan Dennett is. His book Consciousness Explained is probably the best-known contemporary philosophical work on consciousness from a materialist perspective. Today I'll argue that Dennett should, by his own lights, accept the view that the United States is conscious -- that is, the view that the United States has a stream of subjective experience over and above the individual experiences of its residents and citizens, the view that there's "something it's like" to be the United States, as truly as there is something it's like to be you and me.

I offer these reflections not as an attempted refutation of Dennett's view. I think that the literal consciousness of the United States is a real possibility that merits serious consideration.

To start, Dennett is liberal about entityhood. In his essay "Real Patterns", Dennett accepts the real or real-enough existence of things like the his "lost sock center", the center of the smallest sphere than can be inscribed around all the socks he has ever lost. Dennett also appears comfortable with spatially distributed thinking subjects whose parts are connected by radio signals (e.g., Ned Block's Chinese Nation, accepted as conscious in Consciousness Explained, and a fictionalized version of himself in his essay "Where Am I?"). Dennett should have no trouble granting that the United States is a real or real-enough entity that could at least potentially have mental states.

And Dennett is similarly liberal about the ascription of beliefs and desires. In Dennett's view, as long as an entity is usefully describable as possessing beliefs and desires and acting rationally upon them -- as long as belief-desire ascriptions capture some pattern in the entity's behavior that would be left out or much more difficult to see without the help of belief-desire ascriptions -- then that entity has beliefs and desires. Even chess-playing computers qualify. (See especially his book The Intentional Stance.) It seems clear that the United States is usefully describable as having beliefs and desires. The United States wants Iran to cease pursuing nuclear technology. The United States believes that stable democracies make better international partners than do Islamic theocracies.

Thus, it seems clear that Dennett should accept that the United States is a real entity with real beliefs and desires. Ascribing attitudes to this entity helpfully captures "real patterns" in world politics. This isn't an especially unusual view in contemporary philosophy. What's highly unusual is ascribing literal consciousness to group entities.

And about consciousness Dennett is conservative. He's hesitant to ascribe full-blown consciousness even to non-human mammals. He argues that consciousness is a vague-bordered concept from folk psychology that begins to break down when applied to their simpler minds (e.g., here).

Why does consciousness-talk break down, exactly, on Dennett's view? Dennett argues that consciousness requires being an agent with a point of view. That is, consciousness requires "private, perspectival, interior ways of being apprised of some limited aspects of the wider world and our bodies' relations to it"; and this point of view should be conceivably shapable into a narrative if the entity could talk (for the quote, see here, p. 173). That sounds pretty fancy! But it's clear that Dennett intends "private", "perspectival", and "point of view" minimalistically in remarks of this sort, rather than with the full trappings of robust humanocentrism. This minimalism is evident from his assertion that even cherry trees and microphones meet a first-pass application of these criteria. For Dennett, what distinguishes human beings, fully capable of conscious experience, from beings incapable of consciousness and beings in the gray zone, is that the kind of environmental responsiveness possessed by cherry trees and simple robots is directed simply outward, whereas our own responsiveness is also directed at our own states, in complex, recursive, self-regulating loops.

So the question, then, for the Dennettian view, is whether the United States is a gray-zone case in this respect, or whether it has a sufficiently sophisticated perspective on its own internal states. Is its play of representation and responsiveness massively simpler than that of a conscious human being, on the order of the organization of a non-human mammal? Or is its recursive, complex self-sensitivity roughly human magnitude or more? The latter seems the more plausible. The United States, considered as a single, massive system, is vastly complex, arguably embracing within it much of the complexity of each human being who helps compose it. The complex and self-referential structures internal to citizens' minds, and between citizens in conversation, feeds our choices of President, our decisions to war, our environmental policies. That the people of the United States don't agree but adopt multiple competing perspectives is no objection here, and in fact fits very nicely with Dennett's remarks about consciousness involving multiple drafts and "fame in the brain". Both in the U.S. and in the individual human mind, subsystems with inconsistent perspectives compete for control of behavior and meaning-making.

Dennett emphasizes the importance of language and narratives in generating the complexities necessary for consciousness. And the United States exudes language. It apologizes to the descendants of slaves. It announces official foreign policies. It promises to reduce global warming. This isn't the same thing as any single individual apologizing, announcing, or promising, or any several individuals doing so in unison. It's one thing for Obama to apologize and quite another for the U.S. to apologize, even if the U.S. does so using Obama's mouth.

The U.S. even seems to generate "heterophenomenological" self-reports about the processes by which it reaches its beliefs and decides among its actions. We can ask the Census Bureau about its methods for counting residents. We can ask the National Archives and Records Administration how the President is chosen. Congressional leaders sometimes (dubiously) describe the methods by which the governing body has reached its decisions. Dennett seems happy to count even simple computer outputs as "heterophenomenological reports", if they present themselves as descriptions of the computer's internal workings (e.g., "Shakey" in Consciousness Explained, "Cog" in "The Case for Rorts" -- though actually existing robot systems may still be too simple to be literally conscious on Dennett's view). I see no Dennettian grounds for excluding bureaucratic self-descriptions as heterophenomenological reports, by the United States, of its internal workings. Indeed, few if any of us achieve bureaucratic heights of linguistic self-report.

Since Dennett has a generally pragmatic attitude about mental-state ascriptions, one potential Dennettian hesitation is that ascribers might too swiftly leap from what they think they know about human consciousness to conclusions about the conscious experiences of the United States. If you're upset about Iran's pursuit of nuclear technology, there might be some physiological changes in your stomach that contribute to your experience. If the U.S. is upset about Iran's pursuit of nuclear technology, its internal changes will be structurally rather different. But the correct advice here should be pragmatic caution in our heterophenomenological explorations. The same caution would be required if we met cognitively sophisticated aliens very structurally different from us. The same caution would be required in evaluating robots capable of outputs that are linguistically interpretable as sophisticated self-reports of their internal workings -- robots that Dennett argues should be viewed as conscious (e.g., in "The Case for Rorts").

I conclude that philosophers of a broadly Dennettian bent should accept that the United States has a stream of experience in the same sense that you and I do. That we tend to think otherwise, they should say, is merely evolutionarily and developmentally comprehensible, but theoretically ungrounded, morphological prejudice against discontiguous entities.

[Revised Feb. 10.]

Friday, February 03, 2012


A new blog targeted at philosophy students, by Jesse Steinberg at Pitt-Bradford.

Wednesday, February 01, 2012

The Egg Came First

It is only natural that, when confronted with timeless and confounding questions, your friends should turn to you, the philosopher. Sooner or later, then, they will ask you which came first, the chicken or the egg. You must be prepared to discuss this issue in pedantic depth or lose your reputation for intimidating scholarly acumen. Only after understanding this issue will you be prepared for even deeper and more troubling questions such as "Is water wet? Or is water only something that makes other things wet?"

The question invites us to consider a sequence of the following sort, stretching back in time: chicken, egg, chicken, egg, chicken.... The first term of the series can be chosen arbitrarily. The question is the terminus. If one assumes an infinite past and everlasting species, there may be no terminus. However, the cosmological assumptions behind such a view are highly doubtful. Therefore, it seems, there must be a terminus member of the series, temporally first, either a chicken or an egg. The question which came first is often posed rhetorically as though it were obvious that there could be no good epistemic grounds for choice. However, as I aim to show, this appearance of irresolvability is misleading. The egg came first.

Young Earth Creationist views merit brief treatment. If God created chickens on the Fourth Day along with "every kind of winged creature", then the question is whether He chose to create the chicken first, the egg first, both types simultaneously, or a being at the very instant of transition between egg and chicken (when it is arguably either both or neither). The question thus dissolves into the general mystery of God's will. Textual evidence somewhat favors either the chicken or both, since God said "let birds fly above the earth" and the Bible then immediately states "and so it was", before transition to the Fifth Day. So at least some winged creatures were already flying on the Fourth Day, and one day is ordinarily insufficient time for eggs to mature into flying birds. Since chickens aren't much prone to fly, though, it's dubious whether such observations extend to them, unless God implemented a regular rule in which winged creatures were created either mature or simultaneously in a mix of mature and immature states. And in any case, it is granted on all sides that events were unusual and not subject to the normal laws of development during the first Six Days.

If we accept the theory of evolution, as I think we should, then the chicken derives from a lineage that ultimately traces back to non-chickens. (The issues here are the same whether we consider the domestic chicken to be its own species or whether we lump it together with the rest of gallus gallus including the Red Junglefowl from which the domestic chicken appears to be mostly descended.) The first chicken arose either as a hybrid of two non-chickens or via mutation from a non-chicken. Consider the mutation case first. It's improbable (though not impossible) that between any two generations in avian history, X and X-1, there would be enough differentiation for a clean classification of X as a chicken and X-1 as a non-chicken. Thus we appear to have a Sorites case. Just as it seems that adding one grain to a non-heap can't make it a heap, resulting in the paradox that no addition of single grains could ever make a heap, so also one might worry that one generation's difference could never (at least with any realistic likelihood) make the difference between a chicken and a non-chicken, resulting in the paradox of chickens in the primordial soup.

Now there are things philosophers can do about these paradoxes. Somehow heaps arise, despite the argument above. One simple approach is epistemicism, according to which there really is a sharp line in the world such that X-1 is a non-heap and X is a heap, X-1 is a non-chicken and X is a chicken. On this view, our inability to discern this line is merely an epistemic failure on our part. Apparent vagueness is really only ignorance. Another simple approach is to allow that there really are vague properties in the world that defy classification in the two-valued logic of true and false. On this view, between X, which is definitely a chicken, and X-N, which is definitely a non-chicken, there are some vague cases of which it is neither true nor false that it is a chicken, or somehow both true and false, or somewhere between true and false, or something like that. There are also more complicated views, too, than these, but we needn't enter them, because one key point remains the same across all these Sorites approaches: The Sorites cases progress not as follows: X chicken, X-1 egg, X-2 chicken, X-3 egg, X-4 chicken.... Rather, they progress in chicken-egg pairs. From a genetic perspective, since the chicken and egg share DNA, they form a single Sorites unit. Within this unit, the egg clearly comes first, since the chicken is born from the egg, sharing its DNA, and there is a DNA difference between the egg and the hen from which that egg is laid. For a ridiculous argument to the contrary, see here.

If we turn to the possibility of speciation by hybridization, similar considerations apply.

A much poorer argument for the same conclusion runs as follows: Whatever ancestor species gave rise to chickens presumably laid eggs. Therefore, there were eggs long before there were chickens. Therefore, the egg came first. The weakness in this argument is that it misconstrues the original question. The question is not "Which came first, chickens or eggs?" but rather "Which came first, the first chicken or the first chicken egg?"

However, the poverty of this last argument does raise vividly the issue of how one assigns eggs to species. The egg-first conclusion could be evaded if we typed eggs by reference to the mother: If the mother is a chicken, the egg is a chicken egg; if the mother is not a chicken, the egg is not a chicken egg. David Papineau succinctly offers the two relevant considerations against such a view here. First, if we type by DNA, which would seem to be the default biological standard, the egg shares more of its DNA with the hatchling than with its parent. Second, as anyone can see via intuitive armchair reflection on a priori principles: "If a kangaroo laid an egg from which an ostrich hatched, that would surely be an ostrich egg, not a kangaroo egg."

(HT: Walter Sinnott-Armstrong, who in turn credited Roy Sorenson.)

Update, Feb. 2:
In the comments, Papineau reveals that he has recanted in light of considerations advanced by Mohan Matthen in his important but so far sadly neglected "Chicken, Eggs, and Speciation" -- considerations also briefly mentioned by Ron Mallon in his comment. Although I find merit in these remarks, I am not convinced and I believe Papineau has abandoned the egg-first view too precipitously.

Matthen argues that: "Speciation occurs when a population comes to be reproductively isolated because the last individual that formerly bridged that population to others died, or because this individual ceased to be fertile (or when other integrating factors cease to operate)" (2009, p. 110). He suggests that this event will normally occur when both soon-to-be-chickens and soon-to-be-chicken-eggs exist in the population. Thus, he concludes, a whole population of chickens and eggs is simultaneously created in a single instant. In assessing this view let me note first that depending on the size of the population and its egg-laying habits, this view might suggest a likelihood of chickens first. Suppose that in a small population of ancestral pre-chickens the last bridge individual dies outside of laying season; or suppose that the end of an individual's last laying season marks the end of an individual's fertility. If there are no out-of-season eggs at the crucial moment, then chickens came first.

More importantly, however, Matthen's criterion of speciation leads to highly counterintuitive and impractical results. Matthen defines reproductive isolation between populations in terms of the probability of gene transfer between those populations. (Also relevant to his distinction is the shape of the graph of the likelihood of gene transfer by number of generations, but that complication isn't relevant to the present issue.) But probability of gene transfer can be very sharply affected by factors that don't seem to create comparably sizable influences on species boundaries. So, for example, when human beings migrated to North America, the probability of gene transfer with the ancestral population declined sharply, and soon became essentially zero (and in any case in excess of the probability of gene transfer between geographically coincident hybridizing species). By Matthen's criterion, this would be a speciating event. After Columbus, gene transfer probability slowly rose and by now gene transfer is very high between individuals with Native American ancestry and those without. Thus, by Matthen's criterion, Native Americans were for several thousand years a distinct species -- not homo sapiens! -- and now they are homo sapiens again. If the moment of change was Columbus's first landing (or some other discrete moment), then the anchoring of a ship, or some other event, perhaps a romantic interlude between Pocahontas and John Smith, caused everyone on the two continents simultaneously to change species!

More simply, we might imagine a chicken permanently trapped in an inescapable cage. Its probability of exchanging genes with other individuals is now zero. Since Matthen allows for species consisting of a single individual, this chicken has now speciated. Depending on how we interpret the counterfactual probabilities, we might even imagine opening and shutting the door repeatedly (perhaps due to some crazy low-probability event) causing that individual to flash repeatedly back and forth between being a chicken and being a non-chicken, with no differences in morphology, actual behavior, location, or sexual preference during the period. On the surface, it seems that Matthen's criterion might even result in all infertile individuals belonging to singleton species.

There are both philosophical and practical biological reasons not to lightly say that individuals may change species during their lifetimes. One consideration is that of animal identity. If I point at an individual chicken and ask at what point the entity at which I am pointing ceases to exist, there are good practical (and maybe metaphysical) reasons to think that the entity does not cease to exist when a single feather falls off, nor to think that it continues to exist despite being smushed into gravy. The most natural and practical approach, it seems, is to say that the entity to which I intend to refer (in the normal case) is essentially a chicken and thus that it continues to exist exactly as long as it remains a chicken. Consequently, on the assumption that the individual pre-chicken avians don't cease to exist when they become reproductively isolated, they remain non-chickens despite overall changes in the makeup of the avian population. (These individuals may, nonetheless, give birth to chickens.) Nor does it seem that any important scientific biological purpose would be served by requiring the relabeling of individual organisms, depending on population movements, once those organisms are properly classified. Long-enduring organisms, such as trees, seem best classified as members of the ancestral population they were born into, even if their species has moved on since. Long-lived individuals can remain as living remnants of the ancestral species -- a species with temporally ragged but individual-respecting borders. The attractiveness of this view is especially evident if we consider the possibility of thawing a long-frozen dinosaur egg.

Matthen argues as follows against the those who embrace either an egg-first or a chicken-first view: The first chicken would need to have descendants by breeding with a non-chicken, but since by definition species are reproductively isolated this view leads to contradiction. This consequence is easily evaded with the right theory of vagueness and a suitable interpretation of the reproductive isolation criterion. On my preferred theory of vagueness, there will be individuals of which it's neither determinately true nor determinately false that they are chickens. We can then define reproductive isolation as the view that no individual of which it is determinately true that it is a member of species X can reproduce with an individual of which it is determinately false that it is a member of species X. As long as all breeding is between determinate members and individuals in the indeterminate middle, the reproductive isolation criterion is satisfied. (This is not to concede, however, that species should be defined entirely in terms of reproductive isolation, given the problems in articulating that criterion plausibly, some of which are noted above.)

Second update, Feb. 3:
The issues prove even deeper and more convoluted than I thought! In the comments section, Matthen has posted a reply to my objections, which we pursue for a couple more conversational turns. Although I'm not entirely ready to accept his account of species, I see merit in his thought that the best unit of evaluation might be the population rather than the individual, and if there is a first moment at which the population as a whole becomes a chicken population (rather than speciation involving temporally ragged but individual-respecting borders), then that might be a moment at which multiple avians and possibly multiple avian eggs simultaneously become chickens and chicken eggs.

An anonymous reader raises another point that seems worth developing. If we think of "chickens" not exclusively in terms of their membership in a biologically discriminable species but at least partly in terms of their domestication, then the following considerations might favor a chicken-first perspective. Some act of domestication -- either an act of behavioral training or an act of selection among fowl -- was the last-straw change from non-chickenhood to chickenhood, creating the first chicken. But this act was very likely performed on a newly-hatched or adult bird, not on an egg, since eggs are not trainable and hard to discriminate usefully among. Therefore the first entity in the chicken-egg sequence was a chicken, not an egg. For some reason, I find it much more natural to accept the possibility that a non-chicken could become a chicken mid-life if chickenhood is conceived partly in terms of domestication than if it is conceived entirely as a matter of traditional biological species. (I'm not sure how stable this argument is, however, across different accounts of vagueness.)