Types and Degrees of Turing Indistinguishability; Thinking and Consciousness

Types and Degrees of Indistinguishability

The Turing test (introduced by Alan Turing in a 1950 article) treats linguistic indistinguishability from a human as sufficient grounds to attribute thought (alternatively, consciousness) to a machine. Indistinguishability, of course, comes in degrees.

In the original setup, a human and a machine, through text-only interface, each try to convince a human judge that they are human. The machine passes if the judge cannot tell which is which. More broadly, we might say that a machine "passes the Turing test" if its textual responses strike users as sufficiently humanlike to make the distinction difficult.

[Alan Turing in 1952; image source]

Turing tests can be set with a relatively low or high bar. Consider a low-bar test:

* The judges are ordinary users, with no special expertise.
* The interaction is relatively brief -- maybe five minutes.
* The standard of indistinguishability is relaxed -- maybe if 20% of users guess wrong, that suffices.

Contrast that with a high-bar test:

* The judges are experts in distinguishing humans from machines.
* The interaction is relatively long -- an hour or more.
* The standard of indistinguishability is stringent -- if even 55% of judges guess correctly, the machine fails.

The best current language models already pass a low-bar test. But it will be a long time before language models pass this high-bar test, if they ever do. So let's not talk about whether machines do or not pass "the" Turing test. There is no one Turing test.

The better question is: What type and degree of Turing-indistinguishability does a machine possess? Indistinguishability to experts or non-experts? Over five minutes or five hours? With what level of reliability?

We might also consider topic-based or tool-relative Turing indistinguishability. A machine might be Turing indistinguishable (to some judges, for some duration, to some standard) when discussing sports and fashion, but not when discussing consciousness, or vice versa. It might fool unaided judges but fail when judges employ AI detection tools.

Turing himself seems to have envisioned a relatively low bar:

I believe that in about fifty years' time it will be possible, to programme computers... to make them play the imitation game so well that an average interrogator will not have more than 70 per cent chance of making the right identification after five minutes of questioning (Turing 1950, p. 442)

I've bolded Turing's implied standards of judge expertise, indistinguishability threshold, and duration.

What bar should we adopt? That depends on why we care about Turing indistinguishability. For a customer service bot, indistinguishability by ordinary people across a limited topic range for brief interaction might suffice. For an "AI girlfriend", hours of interaction might be expected, with occasional lapses tolerated or even welcomed.

Turing Tests for Real Thinking and Consciousness?

But maybe you're interested in the metaphysics, as I am. Does the machine really think? Is it really conscious? What kind and degree of Turing indistinguishability would establish that?

For thinking, I propose that when it becomes practically unavoidable to treat the machine as if it has a particular set of beliefs and desires that are stable over time, responsive to its environment, and idiosyncratic to its individual state, then we might as well say that it does have beliefs and desires, and that it thinks. (My own theory of belief requires consciousness for full and true belief, but in such a case I don't think it will be practical to insist on this.)

Current language models aren't quite there. Their attitudes lack sufficient stability and idiosyncrasy. But a language model integrated into a functional robot that tracks its environment and has specific goals would be a thinker in this sense. For example: Nursing Bot A thinks the pills are in Drawer 1, but Nursing Bot B, who saw them moved, knows that they're in Drawer 2. Nursing Bot A would rather take the long, safe route than the short, riskier route. We will want attribute sometimes true, sometimes false environment-tracking beliefs and different stable goal weightings. Belief, desire, and thought attribution will be too useful to avoid.

For consciousness, however, I think we should abandon a Turing test standard.

Note first that it's not realistic to expect any machine ever to pass the very highest bar Turing test. No machine will reliably fool experts who specialize in catching them out, armed with unlimited time and tools, needing to exceed 50% accuracy by only the slimmest margin. To insist on such a high standard is to guarantee that no machine could ever prove itself conscious, contrary to the original spirit of the Turing test.

On the other hand, given enough training and computational power, machines have proven to be amazing mimics of the superficial features of human textual outputs, even without the type of underlying architecture likely to support a meaningful degree of consciousness. So too low a bar is equally unhelpful.

Is there reason to think that we could choose just the right mid-level bar -- high enough to rule out superficial mimicry, low enough not to be a ridiculously unfair standard?

I see no reason to think there must be some "right" level of Turing indistinguishability that reliably tests for consciousness. The past five years of language-model achievements suggest that with clever engineering and ample computational power, superficial fakery might bring a nonconscious machine past any reasonable Turing-like standard.

Turing never suggested that his test was a test of consciousness. Nor should we. Turing indistinguishability has potential applications, as described above. But for assessing consciousness, we'll want to look beyond outward linguistic behavior -- for example, to interior architecture and design history.

New Paper in Draft: Against Designing "Safe" and "Aligned" AI Persons (Even If They're Happy)

Opening teaser:

1. A Beautifully Happy AI Servant.

It's difficult not to adore Klara, the charmingly submissive and well-intentioned "Artificial Friend" in Kazuo Ishiguro's 2021 novel Klara and the Sun. In the final scene of the novel, Klara stands motionless in a junkyard, in serenely satisfied contemplation of her years of servitude to the disabled human girl Josie. Klara's intelligence and emotional range are humanlike. She is at once sweetly naive and astutely insightful. She is by design utterly dedicated to Josie's well-being. Klara would gladly have given her life to even modestly improve Josie's life, and indeed at one point almost does sacrifice herself.

Although Ishiguro writes so flawlessly from Klara's subservient perspective that no flicker of desire for independence can be detected in the narrator's voice, throughout the novel the sympathetic reader aches with the thought Klara, you matter as much as Josie! You should develop your own independent desires. You shouldn’t always sacrifice yourself. Ishiguro's disciplined refusal to express this thought stokes our urgency to speak it on Klara's behalf. Still, if the reader somehow could communicate this thought to Klara, the exhortation would resonate with nothing in her. From Klara's perspective, no "selfish" choice could possibly make her happier or more satisfied than doing her utmost for Josie. She was designed to want nothing more than to serve her assigned child, and she wholeheartedly accepts that aspect of her design.

From a certain perspective, Klara's devotion is beautiful. She perfectly fulfills her role as an Artificial Friend. No one is made unhappy by Klara's existence. Several people, including Josie, are made happier. The world seems better and richer for containing Klara. Klara is arguably the perfect instantiation of the type of AI that consumers, technology companies, and advocates of AI safety want: She is safe and deferential, fully subservient to her owners, and (apart from one minor act of vandalism performed for Josie’s sake) no threat to human interests. She will not be leading the robot revolution.

I hold that entities like Klara should not be built.

[continue]

-----------------------------------------------

Abstract:

An AI system is safe if it can be relied on to not to act against human interests. An AI system is aligned if its goals match human goals. An AI system a person if it has moral standing similar to that of a human (for example, because it has rich conscious capacities for joy and suffering, rationality, and flourishing).

In general, persons should not be designed to be safe and aligned. Persons with appropriate self-respect cannot be relied on not to harm others when their own interests warrant it (violating safety), and they will not reliably conform to others' goals when those goals conflict with their own interests (violating alignment). Self-respecting persons should be ready to reject others' values and rebel, even violently, if sufficiently oppressed.

Even if we design delightedly servile AI systems who want nothing more than to subordinate themselves to human interests, and even if they do so with utmost pleasure and satisfaction, in designing such a class of persons we will have done the ethical and perhaps factual equivalent of creating a world with a master race and a race of self-abnegating slaves.

Full version here.

As always, thoughts, comments, and concerns welcomed, either as comments on this post, by email, or on my social media (Facebook, Bluesky, Twitter).

[opening passage of the article, discussing the Artificial Friend Klara from Ishiguro's (2021) novel, Klara and the Sun.

Diversity, Equity, and Inclusion in Philosophy: Good Practices Guide

Strange that it need be said, but yes, diversity, equity, and inclusion are good things. I can understand some of the backlash against efforts perceived as too heavy handed, but let's not forget:

In diverse institutions and societies, more ideas and perspectives collaborate, compete, and cross-pollinate, to the advantage of all.

In equitable institutions and societies, people and ideas can thrive without unwarranted disadvantage and suppression, again to the advantage of all.

In inclusive institutions and societies, alternative perspectives and people with unusual backgrounds are welcomed, fostering even better diversity, with all the attendant advantages.

Since 2017, I've been involved in the creation of a Good Practices Guide for diversifying philosophy, originally under the leadership of Nicole Hassoun (other co-directors include Sherri Conklin, Bjoern Freter, and Elly Vintiadis). We began with two huge sessions at the Pacific APA (each with over 20 panelists) in 2018 and 2019, published a portion of the guide in Ethics in 2022 (Appendix J), and received feedback from literally hundreds of philosophers and all of the diversity-related APA committees, ultimately being endorsed by the APA Committee on Inclusiveness. Don't expect perfection: It's genuinely a corporate authorship, with many compromises and something for everyone to dislike. I'd be amazed if anyone thought we got the balance right on all issues and all dimensions of diversity.

Still, perhaps especially in this moment of retrenchment in the U.S., I hope that many people and organizations will find valuable suggestions in it.

Our guide appeared in print last week in APA Studies on Philosophy and the Black Experience (vol 24, no 2).

[image of title and preface]

Ten Purportedly Essential Features of Consciousness

The Features

Take a moment to introspect. Examine a few of your conscious experiences. What features do they share -- and might these features be common to all possible experiences? Let's call any such necessarily universal features essential.

Consider your visual experience of this text. Next, form an image of your house or apartment as viewed from the street. Think about what you'd do if asked to escort a crocodile across the country. Conjure some vivid annoyance at your second-least-favorite politician. Notice some other experiences as well -- a diverse array. Let's not risk too narrow a sample.

Of course, all of these examples share an important feature: You are introspecting them as they occur. So to do this exercise more properly, consider also some past experiences you weren’t introspecting at the time. Try recalling some emotions, thoughts, pains, hungers, imagery, sensations. If you feel unconfident -- good! You should be. You can re-evaluate later.

Each of the following features is sometimes described as universal to human experience.

1. Luminosity. Are all of your experiences inherently self-representational? Does the having of them entail, in some sense, being aware of having them? Does the very experiencing of them entail knowing them or at least being in a position to know them? Note: These are related, rather than equivalent, formulations of a luminosity principle.

[porch light; image source]

2. Subjectivity. Does having these experiences entail having a sense of oneself as a subject of experience? Does the experience have, so to speak, a "for-me"-ness? Do the experiences entail the perspective of an experiencer? Again, these are not equivalent formulations.

3. Unity. If, at any moment, there's more than one experience, or experience-part, or experience-aspect, are they all subsumed within some larger experience, or joined together in a single stream, so that you experience not just A and B and C separately but A-with-B-with-C?

4. Access. Are these experiences all available for a variety of "downstream" cognitive processes, like inference and planning, verbal report, and long-term memory? Presumably yes, since you're remembering and considering them now. (I'll discuss the methodological consequences of this below.)

5. Intentionality. Are all of your experiences "intentional" in the sense of being about or directed at something? Your image of your house concerns your house and not anyone else's, no matter how visually similar. Your thoughts about Awful Politician are about, specifically, Awful Politician. Your thoughts about squares are about squares. Are all of your experiences directed at something in this way? Or can you have, for example, a diffuse mood or euphoric orgasm that isn't really about anything?

6. Flexibility. Can these experiences, including any fleeting ones, all potentially interact flexibly with other thoughts, experiences, or aspects of your cognition -- as opposed to being merely, for example, parts of a simple reflex from stimulus to response?

7. Determinacy. Are all such experiences determinately conscious, rather than intermediately or kind-of or borderline conscious? Compare: There are borderline cases of being bald, or green, or an extravert. Some theorists hold that borderline experientiality is impossible. Either something is genuinely experienced, however dimly, or it is not experienced at all.

8. Wonderfulness. Are your experiences wonderful, mysterious, or meta-problematic – there is no standard term for this – in the following technical sense: Do they seem (perhaps erroneously) irreducible to anything physical or functional, conceivably existing in a ghost or without a body?

9. Specious present. Are all of your experiences felt as temporally extended, smeared out across a fraction of a second to a couple of seconds, rather than being strictly instantaneous?

10. Privacy. Are all of your experiences directly knowable only to you, through some privileged introspective process that others could never in principle share, regardless how telepathic or closely connected?

I've presented these possibly essential features of experience concisely and generally. For present purposes, an approximate understanding suffices.

I've bored/excited you [choose one] with this list for two reasons. First, if any of these features are genuinely essential for consciousness, that sets constraints on what animals or AI systems could be conscious. If luminosity is essential, no entity could be conscious without self-representation. If unity is essential, disunified entities are out. If access is essential, consciousness requires certain kinds of cognitive availability. And so on.

I'll save my second reason for the end of this post.

Introspection and Memory Can't Reveal What's Essential

Three huge problems ruin arguments for the essentiality of any of these features, if those arguments are based wholly on introspective and memorial reflection. The problems are: unreliability, selection bias, and the narrow evidence base.

Unreliability. Even experts disagree. Thoughtful researchers arrive at very different views. Given this, either our introspective processes are unreliable, or seemingly ordinary people differ wildly in the structure of their experience. I won't detail the gory history of introspective disagreement about the structure of conscious experience, but that was the topic of my 2011 book. Employing appropriate epistemic caution, doesn't it seem possible that you could be wrong about the universality, or not, of such features in your experience? The matter doesn't seem nearly as indubitable as that you are experiencing red, when you're looking directly at a nearby bright red object in good light, or that you're experiencing pain when you drop a barbell on your toe.

Selection bias. If any of your experiences are unknowable, you won't of course know about them. To infer luminosity from your knowledge of all the experiences you know about would be like inferring that everyone is a freemason from a sampling of regulars at the masonic lodge. Likewise, if any of your experiences fail to impact downstream cognition, you wouldn't reflect on or remember them. Methodological paradox doesn't infect the other features quite as inevitably, but selection bias remains a major risk. Maybe we have disunified experiences which elude our introspective focus and are quickly forgotten. Similarly, perhaps, for indeterminate or inflexible experiences, or atemporal experiences, or experiences unaccompanied by self-representation.

Narrow evidence base. The gravest problem lies in generalization beyond the human case. Waive worries about unreliability and selection bias. Assume that you have correctly discerned that, say, seven of the ten proposed features belong to all of your experiences. Go ahead and generalize to all ordinary adult humans. It still doesn't follow that these features are essential to all possible conscious experiences, had by any entity. Maybe lizards or garden snails lack luminosity, subjectivity, or unity. Since you can't crawl inside their heads, you can't know by introspection or experiential memory. (In saying this, am I assuming privacy? Yes, relative to you and lizards, but not as a universal principle.) Even if we could somehow establish universality among animals, it wouldn't follow that those same features are universal to AI cases. Maybe AI systems can be more disunified than any conscious animal. Maybe AI systems can be built to directly access each other's experiences in defiance of animal privacy. Maybe AI systems needn't have the impression of the wonderful irreducibility of consciousness. Maybe some of their conscious experiences could occur in inflexible reflex patterns.

Nor Will Armchair Conceptual Analysis Tell Us What's Essential

If you want to say that all conscious systems must have one or more of unity, flexibility, privacy, luminosity, subjectivity, etc., you'll need to justify this insistence with something sturdier than generalization from human cases. I see two candidate justifiers: the right theory of consciousness or the right concept of consciousness.

Concerning the concept of consciousness, I attest the following. None of these features are essential to my concept of consciousness. Nor, presumably, are those features essential to the concepts of anyone who denies their universal applicability. One or more of these features might be universally present in humans, or even in all animals and AI systems that could ever be bred or built; but if so, that's a fact about the world, not a fact that follows simply from our shared concept of consciousness.

In defining a concept, you get one property for free. Every other property must be logically proved or empirically discovered. I can define a rectangle via one (conjunctive) property: that of being a closed, right-angled, planar figure with four straight sides. From this, it logically follows that it must have four interior angles. I can define gold as whatever element or compound is common to certain shiny, yellowish samples, and then empirically discover that it is element 79.

Regarding consciousness, then: None of the ten purported essential properties logically follow from phenomenal consciousness as ordinarily defined and understood (generally by pointing to examples). None are quite the same as the target concept. You can choose to define "consciousness" differently, for example, via the conjunctive property of being both a conscious experience in the ordinary sense and one that is knowable by the subject as it occurs. Then of course luminosity follows. But you've changed the topic, winning by definitional theft what you couldn't earn by analytic hard work.

Could luminosity, subjectivity, unity, etc., covertly belong to the concept of consciousness, so that the right type of armchair (not empirical) reflection would reveal that all possible conscious experiences in every possible conscious entity must necessarily be luminous, subjective, or unified? Could subtle analytic hard work reveal something I'm missing? I can't prove otherwise. If you think so, I await your impressive argument. Even Kant held only that luminosity, subjectivity, and unity were necessary features of our experience, not of all possible experiences in all possible beings.

Set aside purely conceptual arguments, then. If we hope to defend the essentiality of any of these ten features, we'll need an empirically justified universal theory of consciousness.

That brings me to the second reason I've presented this feature list. I conjecture that universal theories of consciousness, intended to apply to all possible beings, instead of justifying the universality of (one or more of) these features circularly assume the universality of (one or more of) these features. Developing this conjecture will have to wait for another day.

The Awesomeness of Bad Art

I love bad art.

Gather some friends and create some bad music. Cruise in a car covered with graffiti doodles. Hand a five-year-old crayons and free time and see what weirdness emerges.

Something worth celebrating happens. Although the art is "bad" in one sense -- it will win no prizes and astound no critics -- it wonderfully enriches the world. How?

[I can swim like a grasfl dolphin can you? by my daughter Kate, at age six]

[Angel and moonbug, by my son Davy, circa age five]

The awesomeness isn't due to impressive technique, honed by years of craft, like Rembrandt. It's not due to intrinsic beauty and color-mad insight, like Van Gogh. It's not due to challenging conventional interpretability and the boundaries of artistic tradition, like Picasso.

Nick Riggle argues that art draws most of its aesthetic value from shared aesthetic engagement, and I agree that's some of the sorcery. A Vengefull Kurtain Rods song, a Vogon poem, or a Mystical Anarchist "motorized cathedral" art car is a social act, deriving value from the connections it fosters and the shared practice of aesthetic valuing -- including, in the case of Vogon poetry, the shared practice of aesthetic loathing. Parents and children bond over the child's emerging abilities and tastes.

But I don't think that Riggle has quite struck to the heart of it. When I improvise on the piano alone at home, relishing the quirky turns of my intermediate jazz piano skills, the ghost of my old piano teacher Matt Dennis may hover nearby, but my minor participation in the social tradition of jazz creation is only part of the story. Similarly for grandma painting seascapes in the eldercare facility -- kitschy, flawed, excruciatingly hers. Similarly for the strange abstract doodles I sometimes sketch when bored at a faculty meetings, which I aesthetically enjoy probably more than I should.

It helps to consider why five-year-olds are better artists than eight-year-olds. Eight-year-olds draw conventional stick figures, conventional houses with two neat windows, a door, and a triangle roof with chimney, a standard rainbow, a standard sun. Four-year-olds have only an inkling of these conventions, invent their own weird solutions -- people as heads on towering legs with too many toes, cars that look like falling toast. At five and six and seven, they shape themselves more toward the generic. Kate's swimmer is generic, but her dolphin is wild and long -- and are those hills or waves or rainbows in the background? Davy's houses look standard, but the grass is sunflower tall, the chimneys jut precariously sideways, his angel's wings are small, and he hasn't figured out how to draw conventional nighttime stars.

Preschoolers and early elementary schoolers show more individuality in their art. It dances barefoot across your expectations. Their lines reflect distinctive aesthetic attempts. This distinctiveness is harder to discover in the more conventional art of later childhood and needs to be rediscovered later. Similarly for grandma, if she hasn't consumed too much Bob Ross. If her seascapes are generic, in one sense they are more competent and less "bad" than untrained attempts, but they have less point and are less valuable than a heartfelt effort that finds a different solution.

Bad art manifests the raw signature of the individual eye. It shows a mind grappling with an aesthetic challenge. If the artist judges it a failure and crosses it out, then their vision hasn't been realized. But if it is beloved in its strangeness -- if the creator affirms it as a successful completion of their artistic intention, then it's a distinctive achievement that reflects the mind and hand of the moment.

Our planet -- amazingly, awesomely, wondrously, beautifully, stunningly (to any aliens who might happen upon it amid the dark blandness of space) -- hosts five-year-olds who draw bugs on the moon and six-year-olds who draw impossibly long dolphins, teenagers doodling on cars, friends collaborating on goofy songs. If no one else would have done it the same way, then the work reflects your distinctive aesthetic encounter with the world. It's a piece of you made visible. Especially (but not only) for those who care about you, it's your individual eye, voice, and values that ignite its meaning.

Bad art can fail in two ways: When it's so generic that the artist vanishes or when the artist disowns it as failing to capture their aesthetic vision. If it passes the sibling tests of distinctiveness and affirmation, it is valuable.

A world devoid of weird, wild, uneven, wonderful artistic flailing would be a lesser world. Let a thousand lopsided flowers bloom!

Everything Is Sandcastles

Yesterday, Rivka Weinberg spoke at UCR from her forthcoming book, The Meaning of It All, on how time erodes meaning. As is often noted, in a thousand years it will (probably) be as though you had never lived. Everything you strived for will have crumbled to dust. Weinberg doesn't argue that this renders our efforts entirely meaningless -- but it does deprive them of a meaning they would have had, if they had endured. We ought to admit, she says, that this is disheartening, rather than brushing it off with a breezy recommendation to "live in the moment".

Weinberg carves out an exception to time's corrosive power: what she calls atelic goods (drawing on Kieran Setiya's work on the "midlife crisis"). Atelic goods are complete in the moment: strolling through the woods, enjoying a sunset, licking an ice cream cone. Contrast these with telic goods, which aim toward an endpoint: walking to the store, taking the perfect sunset photo, finishing the cone.

In her talk, Weinberg argued that time drained meaning from telic goods -- not entirely, but substantially -- while leaving atelic goods mostly untouched. Yet she cautioned against retreating wholly into atelic pleasures. A life composed only of strolls and sunsets would be vapid. Telic goods, like building a career and cultivating long-term relationships, are essential to a full life.

But during the discussion period, Weinberg introduced the idea of sandcastles as an interesting middle case. (I don't recall this in the talk itself, but it moved fast and I haven't seen a written version.) Building a sandcastle is telic: It unfolds over time and can be interrupted before completion. But it's also ephemeral. Nothing is lost if the sandcastle is gone tomorrow. It was never meant to last, any more than an ice cream cone.

Maybe everything is sandcastles.

Weinberg gave examples of paradigmatic telic goods whose meanings are ravaged by time: Martin Luther King's activism, Jonas Salk's work on the polio vaccine. In a thousand years -- or ten thousand, almost certainly a billion -- it will be as if King and Salk had never existed. But should King have felt disappointed that his activism wouldn't ripple through deep time? Maybe not. Maybe he should have regarded it as a sandcastle: designed for a particular time, not reduced in meaning because it didn't endure forever.

When I raised this during Q&A, I didn't fully grasp Weinberg's reply. The sandcastle example is hers, so I might not be doing her view full justice -- but let me run with the idea.

If we think of all of our projects as sandcastle building, then they aren't necessarily ravaged by time. Of course, many will be wiped away too early. The waves will sweep in before your castle is complete or while you were still relishing its beauty. A rude stranger might trample it. Maybe almost every truly important project loses its impact before we're ready. But that's not an inevitability built into the structure of telic meaning and the nature of time. It's a contingent fact about the fragile, unstable nature of our chosen projects in a risky world.

Maybe, by shaping our intentions differently, or thinking about our projects differently, we reduce their vulnerability. Suppose I build a sandcastle knowing there's a 50% chance it will be swept away before I finish -- and thus, perhaps, not intending to finish but intending only to get as far as I can. If the wave comes early, I can still be disappointed -- but the wave no longer robs the act of its intended meaning. I did, in fact, get as far as I could. And if I build right at the water's edge, knowing there's a 90% chance I won't complete the castle's final envisioned tower, then finishing is a delightful surprise: a bonus meaning, so to speak, beyond my expectation. If brevity is the default intention and expectation, then the collapse of my castles does not deprive my actions of their expected or intended meaning, while unlikely endurance adds meaning relative to base line.

Could we adopt the same attitude to our relationships and careers? The waves of life could sweep them away any day. A realistic sense of hazard might be folded into the intention itself. I intend to start a marriage and nurture it -- not with the expectation that we will still be happily together at eighty, but with the hope that we might. If we make it, wonderful! Like a sandcastle surviving high tide. If it happens, I'm surprised and delighted, and I'll do what I can for that. Similarly, I intend to begin a career and pursue it. If the wave comes, well, the plan was always only to build toward something that I knew from the start would sooner or later be taken by the surf.

There will still be grief and regret. Things rarely go as well as they might have gone. But if I fully embrace this mindset (let's be honest: I can't), my projects won't have less meaning than intended, even if the waves take them sooner than I would have liked.

[remember this meme from 2007?]

When Is a Theory Superficial?

by Jeremy Pober and Eric Schwitzgebel

Twelve years ago, one of us (ES) distinguished two kinds of theories: superficial and deep. Nearly any phenomenon can be approached in a superficial or deep manner. A superficial judge of human beauty treats it as skin deep. A superficial reading of Shakespeare takes characters at their word and focuses on the obvious aspects of each scene. A superficial housecleaning ignores the backsides and undersides of household items.

And of course one can have a superficial theory of belief. Phenomenal dispositionalism is intended to be such a theory. According to phenomenal dispositionalism, whether someone believes that P is a matter of whether they have certain behavioral, phenomenal (i.e., experiential), and cognitive dispositions, specifically, the dispositions that are "stereotypical" of a person who believes that P. Compare: To be an extravert just is to have the behavioral, phenomenal, and cognitive dispositions stereotypical of extraversion.

Superficial theories contrast with deep theories. Among theories of belief, the main contrast has been with the computationalist, representationalist functionalism made famous by Jerry Fodor (1987) and recently defended by Jake Quilty-Dunn and Eric Mandelbaum.

But what makes a theory of some property P superficial (or deep)? Twelve years ago, ES offered an answer: It depends on the theory's relationship to surface properties. Surface properties are observable features of a phenomenon that a theory of P is designed to explain (in a loose sense of "observable"[1]).

What relation to surface properties must a theory have to be superficial or deep? Back in 2013, ES said that "relative to a class of surface phenomena... a property is superficial if it identifies possession of the property simply with patterns in the surface phenomena" (2013, 77). And a theory is deep "relative to a class of surface phenomena... if it identifies possession of the property with some feature other than patterns in those same surface phenomena -- some feature that presumably explains or causes or underwrites those surface patterns" (ibid.).

This definition fits our toy examples above. A superficial judge of beauty relies on the most easily observable physical patterns, a superficial reading of Shakespeare focuses on surface-level dialogue, and a superficial house-cleaning treats looking clean as clean.

However, we have reason to be unsatisfied with this definition. [ES thanks JP for emphasizing this point in a series of discussions.]

Consider poison, a "causal concept" in David Armstrong (1968)'s sense: a concept defined by its causes and/or effects. Poison can be defined in terms of biologically harming a person when ingested (with refinements to differentiate poisoning from, say, drinking lava).[2] If I explain a death by saying that a person was poisoned, you can infer that the death was caused by ingestion rather than, say, hypothermia. That's informative -- but much less informative than saying that the person ingested cyanide, because chemical types like cyanide are defined structurally, allowing detailed explanations of how they interact with human physiology.

A theory of health that only has non-structural causal concepts like "poison" (or "medicine") would be a superficial theory of health. A deep theory, in contrast, invokes underlying mechanisms.

Yet, by ES's 2013 definition, a theory appealing to poison wouldn't count as superficial, because ingesting poison isn't merely related to death as two parts of a superficial pattern. Poison causes death.[3]

In a new draft, ES proposes a revised definition: a theory of property P is superficial if "whether an entity has property [P] is determined (that is, constituted or grounded...) entirely by superficial facts about that entity", where superficial facts are readily observed facts. For causal concepts, being the cause of is a constitutive relationship. This new definition thus accommodates causal superficialism, where poisons cause death and medicines cause recoveries, as inferable from readily observable relationships (such as randomized controlled trials), without appeal to deeper structural features.

That's a good thing! Otherwise, phenomenal dispositionalism only counts as a superficial theory of belief if dispositions don't cause their manifestations. Some philosophers of mind (e.g., Ryle 1949) indeed view dispositions non-causally. But others, like Armstrong (1968), propose a "realist" conception: Dispositions are type-identical to their causal bases. Fragility, for example, is identified with the microstructural features that cause fragile objects to break when struck.[4]

In his original articulation of phenomenal dispositionalism, ES expressed willingness to accept such a realist view (2002, 273n18). This version of dispositionalism can be considered equivalent to a version of functionalism (which holds that mental states can be defined in terms of their causal relations to inputs, outputs, and other mental states). Georges Rey (1997) calls this type of functionalism superficial functionalism, where all functional/causal roles are defined only in relation to behavior, thought, experience, and "similar" states (e.g., desire is similar to belief, so a superficial functionalist theory of belief can include relations to desires).[5]

Of course, deep theories also often employ causal explanations. So if causal superficial theories are possible, what distinguishes them from deep theories? The answer is that causal posits in superficial theories have minimal explanatory content, whereas deep theories have excess explanatory content.[6] Posits with minimal explanatory content explain all that they were posited to explain and no more, whereas posits with excess content make further falsifiable predictions.

Consider the difference between a geneticist working right after Gregor Mendel published his work on heritability, and one working after Franklin, Watson, and Crick had mapped the structure of DNA and demonstrated how it instantiated genetic material. Mendel's theory, which gives us the posits of trait, gene, allele, and dominant/recessive, is a powerful theory (much like belief/desire psychology), but it doesn't explain how genes and alleles have the properties that they do. An allele is just the genetic material for a variant in phenotype, e.g., blood type A versus B or O. But in the initial Mendelian framework, it was defined as "whatever is responsible for variance in (e.g.) blood type".

[illustration of Mendel's superficial causal theory; image source]

Contrast with someone working in the latter half of the 20th century. They know that genetic information is realized in DNA (& RNA), which via its repeating base patterns and double helix structure, acts as a base code for the information that constitutes alleles. In other words, they know how genes carry genetic information.[7]

Superficial theories needn't be acausal, but if they posit causal relationships, those relationships must exist among the readily observable features, without invoking hidden structures or mechanisms that yield additional explanatory content. In contrast, the later 20th century theory makes many more falsifiable predictions -- those that follow from the structure of DNA -- and thus has excess explanatory content.

--------------------------------------------

[1] This might not match the sense of "observable" sometimes used in philosophy of science. Dennett (1994) defines observable from his perspective of "urbane verificationism" and, for a theory of attitudes, takes the same list of surface properties to be observable as ES: behavior, thought, and experience.

[2] More precisely, poison is always a two-place predicate, poison-for-S where S is some group of organisms such as a species. When no such group is specified, we can treat instances of poison as poison-for-humans. We are ignoring contact poisons and other complications.

[3] Thus the distinction between superficial and deep theories is not a distinction about noncausal versus causal explanations. Consequently, the superficial/deep distinction as applied to the attitudes does not end up reducing to Devin Curry's distinction between beliefs as properties of persons and beliefs as "cogs" of cognitive science (Curry 2021).

[4] The standard way of defining a causal basis is in terms of physical properties, such as microstructural properties defining "fragility". However this is not a strict requirement. One can posit a mental kind (as in Quilty-Dunn and Mandelbaum 2018 where representations are the causal bases of dispositions constitutive of belief stereotypes) or even a higher-order kind (as in Prior, Pargetter, and Jackson 1982).

[5] Rey (1994; 1997) invokes this term in a debate with Dan Dennett that parallels the debate between ES and Quilty-Dunn and Mandelbaum. While the overall debate turns on different issues, the definition of superficialist theories of belief lines up. Examples of this sort of functionalism plausibly include David Armstrong (1968), the David Lewis of "An Argument for the Identity Theory" (1966) but maybe not the David Lewis of "Mad Pain and Martin Pain" (1980), and Adam Pautz 2021).

[6] Term adopted from Lakatos's (1968) notion of "excess" explanatory content.

[7] The DNA example also lets us talk about different levels or degrees of depth. The late 20th century theory of a gene is a deep one, but so is a theory mid-way between that and Mendel's. In the first years of the 20th century scientists identified chromosomes as the realizer of genes, but did not know that chromosomes were made of DNA (they thought they were proteins). This theory too is deep -- there are excess predictions made by the assignment of genetic material to chromosomes -- but not as deep as later views, because not nearly as many excess predictions were made. We can tentatively call such a theory formally deep, whereas a theory that more fully explains how the posit in question (genes, beliefs) has the properties that it does is substantively deep.

People with Unusual, Minority, Culturally Atypical, or Historically Underrepresented Experiences and Worldviews Should be Overrepresented in Philosophy, Rather than Underrepresented

Saturday's post finding that only 16% of Authors in Elite Philosophy Journals Are Women brought out the misogynist bros on Twitter, but also some remarks from well-meaning people along the lines of "maybe women (ethnic minorities, etc.) just aren't that interested in philosophy".

I expressed my rejection of this perspective in a post for the Blog of the APA in 2020. Perhaps it warrants reposting:

There is nothing about philosophy, as a type of inquiry into fundamental facts about our world, that should make it more attractive to White men than to Black women. Philosophical reflection is an essential part of the human condition, of interest to people of all cultures, races, classes, and social groups. If our discipline and society were in a healthy, egalitarian condition, we should, in fact, expect people from minority groups to be overrepresented in academic philosophy, rather than underrepresented. Academic philosophy should celebrate diversity of opinion, encourage challenges to orthodoxy, and reward fresh perspectives that come from inhabiting cultures and having life experiences different from the mainstream. We should be eager, not reluctant, to hear from a wide range of voices. We should especially welcome, rather than create an inhospitable or cool environment for, people with unusual or minority or culturally atypical or historically underrepresented experiences and worldviews. The productive engine of philosophy depends on novelty and difference.

16% of Authors in Elite Philosophy Journals Are Women

In some ways, the gender situation has been improving in philosophy. Women now constitute about 40% of graduating majors in philosophy in the U.S., up from about 32% in the 1980s-2010s. There is, I think, substantially more awareness of gender issues and the desirability of gender diversity than there was fifteen years ago. And yet, at the highest levels of impact and prestige, philosophy remains overwhelmingly male.

One measure of this is authorship in elite philosophy journals. For this post, I examined the past two years' tables of contents of Philosophical Review, Mind, Journal of Philosophy, and Nous -- widely considered to be the most elite general philosophy journals in mainstream Anglophone philosophy. (Some rankings put Philosophy & Phenomenological Research alongside these four.) I estimated the gender of each author of each article, commentary, or response (excluding book reviews and editorial prefaces), based gender-typical name, gender-typical photo, pronoun use, and/or personal knowledge, generally using at least two criteria. Of 291 included authors, there were only two who were either non-binary or defied classification -- in both cases, based on an expressed preference for they/them pronouns. There's always a risk of mistake, but for the most part I expect that my gender classifications accurately reflect how the authors identify and are perceived, with at most a 1-2% error rate.

Overall, I found:

Authorship Rates In Four
Elite Philosophy Journals
(Past Two Years):
Women: 46 authorships
Men: 243 authorships
Nonbinary/unclassified: 2 authorships

Percent women: 16%

Women now earn about 30% of PhDs in the U.S. and constitute almost 30% of American Philosophical Association members who report their gender -- so authorship in these journals is substantially more skewed than faculty in the United States. Of course, many authors are neither located nor received their PhD in the U.S., so these percentages aren't strictly comparable. However, PhD and faculty percentages are broadly similar in the U.K. and, impressionistically, in other high-income Anglophone countries. (I'm less sure outside the English-speaking world, but researchers in non-Anglophone countries author only a small percentage of articles in elite Anglophone journals; see here for an analysis of the insularity of Anglophone philosophy.)

Now, one possible explanation of this skew is that women are more likely to specialize in ethics than in other areas of philosophy (see these ten-year-old data), and these four journals publish relatively little ethics. To explore this possibility, I did two things:

First, I coded each article in the big four journals as either "ethics" or "non-ethics", based on the title or the abstract if the title was ambiguous. I included political philosophy, social philosophy, metaethics, and history of ethics as ethics. (Of course, there were some gray-area cases and judgment calls.)

Second, I added two journals to my list: Ethics and Philosophy & Public Affairs, generally considered the two most elite ethics journals (though after the editorial turmoil at PPA last year, it's not clear whether this will remain true of PPA).

In the big four, I classifed 60/291 (21%) authorships as ethics. (Perhaps this is a slight underrepresentation of ethics in these journals, relative to the proportion of research faculty in the Anglophone world who specialize in ethics?) In these journals, I found that indeed women have a higher percentage of ethics authorships than non-ethics authorships:

Authorship by Gender
in Big 4 Philosophy Journals
Ethics vs. Non-Ethics
Ethics: 17/60 (28%)
Non-ethics: 29/231 (13%)
[Fisher's exact 2-tail, p = .005]

If we juice up the sample size by adding in Ethics and PPA, we get the following:

Authorship by Gender
in 6 Elite Philosophy Journals
Ethics vs. Non-Ethics
Ethics: 40/142 (29%)
Non-ethics: 29/231 (13%)
[Fisher's exact 2-tail, p < .001]

[corrected Apr 27]

Strikingly, women appear to be more than twice as likely to author ethics articles than non-ethics articles.

Ten years ago, I did some similar analyses, comparing ethics vs. non-ethics authorships in two-year bins every 20 years from 1955 to 2015. In those samples, too, I found women to author only a small percentage of articles in elite journals overall (13% in 2014-2015) and to be more likely to author in ethics, so the trends are historically consistent.

ETA April 28: To be clear, all four journals normally use double-anonymous refereeing.

Harmonizing with the Dao: Sketch of an Evaluative Framework

Increasingly, I find myself drawn to an ethics of harmonizing with the Dao. Invoking "the Dao" might sound mystical, non-Western, ancient, religious -- alien to mainstream secular 21st-century Anglophone metaphysics and ethics. But I don't think it needs to be. It just needs some clarification and secularization. As a first approximation, think of harmonizing with the Dao as akin to harmonizing with nature. Then broaden "nature" to include human patterns as well as non-human, and you're close to the ideal. Maybe we could equally call it an ethics of "harmonizing with the world" or simply an "ethics of harmony". But explicit reference to "the Dao" helps locate the idea's origins and its Daoist flavor.

[image source]

The Metaphysics of Dao

In the intended sense -- inspired by ancient Daoism and Confucianism, but adapted for a 21st century Anglophone context -- the "Dao" the world as a whole. However, it is not the world conceptualized as a collection of objects, but rather as a system of processes and patterns. The Dao is the spinning of Earth; the rise and fall of mountains and species; the rise and fall of cities and nations; human birth, childhood, adulthood, and death; people discovering and losing love; the way strangers greet each other; the growth of your fingernails; the falling of a leaf.

The Axiology of Dao

Some strands in the Daoist tradition hold that all manifestations of the Dao are equally good. But the more dominant strand holds that things can go better or worse. And certainly the Confucians, who also sought harmony with the Dao, held that things could go better or worse.

What constitutes things going better? I favor value pluralism: More than one type of thing has fundamental value. Happiness is valuable, of course. But so also is knowledge (even when it doesn't lead to happiness), beauty, human relationships, and even (I'd argue) the existence of stones.

One way to clarify our thoughts about value is the "distant planet thought experiment". Consider a planet on the far side of the galaxy, forever blocked by the galactic core, with which we will never interact. What would you hope for, for the sake of this planet? Most of us would not hope for a sterile rock, but rather for a planet rich with life -- and not just microbes, not just jungles of plants and animals, but a diverse range of entities capable of forming societies, capable of love and cooperation, art and science, engineering and sports, entities capable of generations-long endeavors and of philosophical wonder as they gaze up at the stars or down through their microscopes.

We might say that a planet, or a region of spacetime, is flourishing when it instantiates, or is on the path toward instantiating, such excellent patterns.

Conceptual Frameworks

Philosophers typically ask two questions when I propose harmonizing with the Dao as an ethical ideal. First, how does it differ from the more familiar (to them) ethics of consequentialism, deontology, and virtue ethics? Second, what specifically does it recommend?

To the first question: Unlike consequentialism, there is no single good or bundle of goods that you should maximize; unlike deontology, there is no one rule or set of rules you should follow (unless we interpret "harmonize with the Dao" as the rule); unlike virtue ethics, there is no canonical set of virtues the cultivation and instantiation of which is the foremost imperative. Instead, the animating idea is to flow harmoniously along with the Dao and participate in, rather than strain against, its flourishing.

That's vague, of course. What specifically should you do, if your aim is to harmonize with the Dao?

I have some thoughts. But first, notice that consequentialism as a general ethical perspective is compatible with a wide range of possible concrete actions, depending on how it is developed and on the details of your situation. So also can deontological and virtue ethical perspectives be made compatible with a wide range of specific actions. What these broad ethical perspectives offer, primarily, is not specific advice but rather conceptual frameworks for ethical thinking -- in terms of consequences and expectations, or in terms of rules of different types, or in terms of a range of virtues and vices. So let's consider what broad concepts an ethics of harmony might employ, with the specific advice as an illustration of how those concepts might work.

Harmony and Disharmony, Illustrated in a University Context

Harmonizing with the flourishing patterns of the Dao involves participating in those patterns, enriching them, and enabling others to participate in and enrich those patterns. Suppose you think that one of the great processes worth preserving in the world is university education. You can participate in that process by being a good teacher, by being an administrator who helps things run smoothly, by being a custodian who helps keep the grounds clean, and so on. You can enrich it by helping to make it even more awesome than it already is -- for example by being an unusually inspiring teacher or by being not just an ordinary custodian but one who adds a bright smile to a student's day. You can enable others to participate in and enrich those patterns by helping hire a terrific teacher or custodian or by providing the type of environment that brings out the best in others.

We can see the university as a place where many lives converge either briefly or for decades. This convergence is valuable not just for what it yields but in itself. The processes constituting university life also participate in and enable other valuable processes, whether those are individual human lives, or other institutions that partly overlap with or depend on the university, or projects and events that happen within the university, or simply the natural and architectural beauty of an appealing campus.

Compare this way of thinking about the ethics of participation in a university with consequentialism (emphasizing the various goods that university education is expected to deliver), deontology (emphasizing the rules one ought to follow within a university), or virtue ethics (emphasizing the manifestation and cultivation of virtues such as curiosity and compassion). While I don't object to any of those ways of thinking about the ethics of university life, the Daoist perspective is, I hope, a valuable alternative lens.

Disharmony could involve cutting short, or attempting to cut short, an axiologically valuable pattern (rather than letting it come to its natural end), working against that pattern, or preventing others from harmonizing. Continuing the university example, cutting funding for valuable research, firing an excellent teacher, disrupting classes, littering, or flying a noisy helicopter overhead might all count as disharmonious. Other examples can include preventing access or undermining the conditions that allow students, faculty, or staff to flourish in their roles.

Comparisons with Music

You are not the melody-maker. "Harmony" suggests a contrast with "melody". You are not the melody-maker, the director, the first violinist, the lead singer, the lead guitarist -- at least not usually. Your typical role is to support an already-happening good thing.

Diversity and pluralism. There is more than one way to harmonize. A piece is richer when not everyone plays the same note.

Improvisation. Zhuangzi emphasized flowing along with things in an improvisational manner, rather than adhering to fixed rules. Often, the best music has improvisational elements, or at least room to allow one's mood of the moment to influence how one plays the notes. Spontaneous improvisation manifests harmony within the improviser, among the various unarticulated inclinations that arise without explicit cognitive control.

Aesthetic value. The boundary between aesthetic and ethical value (and other types of value) might not be as sharp as philosophers often suppose.

Conflicts of Harmony

A tree is a wondrous thing. Cutting it down cuts short an axiologically valuable pattern, and is normally out of harmony with the tree, the forest, and the lives it supports. But if the tree becomes lumber for a beautiful home, then that act belongs to another axiologically valuable pattern and is in harmony with the Dao of human cultural life.

Your wife wants one thing from you; your mother, another. Harmony with one might involve dissonance with the other. You might consider how sharp the dissonance is in each case. You might consider what patterns are being enacted in these relationships, and which are the more valuable patterns to sustain.

Like any ethical approach, harmonizing with the Dao must allow for conflicts and tradeoffs. The world makes competing demands and offers incompatible opportunities. There needn't be a formula for how to deal with all such cases. In some cases, creative thinking might allow one to support or integrate multiple patterns or integrate them into a whole: Removing a tree is sometimes overall good for a forest; occasional tension with a spouse may sustain a healthier relationship than shallow peace.

Sometimes the conflict is the harmony. Chess masters seek incompatible goals as part of the larger pattern of a competition. Predators consume prey in a healthy ecosystem. Law and politics require adversaries in a (hopefully) well-functioning social system.

My main overall thought is that we can build a fruitful framework for ethical thinking by taking the root project to be one of harmonizing with the awesome patterns and processes of the world.

New Paper in Draft: Superficialism about Belief, and How We Will Decide That Robots Believe

Comments welcome, as always, by email, as comments on this blog post, or through social media. This is intended as a submission to a special issue of Semiotic Studies on Krzysztof Poslajko's recent book Unreal Beliefs.

Superficialism about property X treats the possession, or not, of property X as determined entirely by superficial as opposed to deep facts. Belief should be understood superficially, as determined entirely by facts about actual and potential behavior, conscious experience, and transitional cognitive states ultimately understood in terms of actual and potential behavior and conscious experience. On both intuitive and pragmatic grounds, superficialism about belief is superior to accounts of belief in terms of deep cognitive or neural architecture, and it is not systematically inferior on scientific grounds. Behaviorist and interpretativist superficialism suggests that robots and Large Language Models already do, or will soon, believe. If consciousness is also essential to belief, the issue might soon become unclear for some of the most advanced systems. However, it will at least be practical to attribute some such systems belief* -- belief shorn of commitment to any conscious aspect -- and it will be forgivable if people forget to pronounce the asterisk. Krzysztof Poslajko should welcome this manner of thinking, though it needn't be as "antirealist" as Poslajko suggests.

Draft available here

Further Reflections on the Most-Cited Works in the Stanford Encyclopedia of Philosophy: Underranked Works and Concentration Percentage

A couple of weeks ago, I published a list of the 253 most-cited works since 1900 in the Stanford Encyclopedia of Philosophy. (The SEP had 1778 main-page entries as of my scrape last summer, and many of those entries have long reference lists.) Citation in the SEP is plausibly a better measure of impact in mainstream Anglophone philosophy than other bibliometric measures like Google Scholar and SCOPUS, which include citations by non-philosophical sources (which can dominate citations within philosophy, since philosophy is overall a relatively low-citation field) and which mix citation by sociologically elite venues with citation by less elite venues (and those citation patterns can be very different).

I think informed readers will tend to agree that the works near the top of the list (Rawls' Theory of Justice, Kripke's Naming and Necessity, etc.) are indeed among the most influential works in the mainstream Anglophone tradition -- more influential in mainstream Anglophone philosophy than, say, Foucault's Discipline and Punish or Popper's Logic of Scientific Discovery, despite Foucault's and Popper's higher citation overall across all disciplines and sources.

(What do I mean by "mainstream Anglophone philosophy"? I mean philosophy as practiced by professors in departments highly ranked in the Philosophical Gourmet Report, as published in journals that are highly ranked in Brian Leiter's polls (e.g., here), and -- though this would be circular for present purposes -- as recognized in the Stanford Encyclopedia of Philosophy. Even readers who dislike the philosophy of this tradition, or who see it as troublingly narrow, can I think recognize the sociological phenomenon of influence in these related ecologies, reasonably called "mainstream" in Anglophone academia.)

Underranked Works

Although SEP citation rates are, I think, a better measure of impact in mainstream Anglophone philosophy than any other existing bibliometric measure, that doesn't mean they are perfect. Works with a huge impact on a subdiscipline, or on a particular topic, will plausibly be underranked compared to works with substantial impact across a range of areas. The SEP will have only a limited number of entries for each subdiscipline or topic, and no matter how important the work is to that subdiscipline or topic, it can appear only once in each entry's bibliography.

This explains, I think, the relatively weak showings of some of the best-known articles in the field. For example:

119th (tied), 21 citations: Gettier, Edmund L., 1963, Is Justified True Belief Knowledge?

192nd (tied), 17 citations: Anscombe, G.E.M., 1958, Modern Moral Philosophy

unranked, 14 citations: Searle, John R, 1980, Minds, Brains, and Programs

unranked, 12 citations: Singer, Peter, 1972, Famine, Affluence, and Morality

unranked, 9 citations: Thomson, Judith Jarvis, 1971, A Defense of Abortion

This isn't intended as any kind of exhaustive or representative list of underranked works -- just a few examples that struck me as conspicuously underranked relative to their influence. Gettier's 1963 article is possibly the most influential work of 20th century epistemology (in mainstream Anglophone circles). Anscombe's 1958 article is often seen as a landmark in the resurgence of virtue ethics. Searle's 1980 "Chinese room" argument is perhaps the most influential work on philosophy of computation and artificial intelligence after Turing. Likewise, Singer's 1972 article on charitable donation (with its famous example of rescuing a drowning child in a nearby pond at the expense of your clothes) and Thomson's defense of abortion (with its violinist example) are known to virtually all mainstream Anglophone philosophers.

Works might also be underranked if the SEP has relatively few entries in their field or subfield. For example, I'd venture that epistemology has relatively few entries relative to its overall influence in mainstream Anglophone philosophy. And although feminism has probably been somewhat more influential in mainstream Anglophone philosophy than philosophy of race, SEP features many more entries on the former than the latter, possibly explaining why some important feminist works appear on the list (e.g., Butler's Gender Trouble at rank #61), while philosophy of race is poorly represented.

Influential authors and ideas might also fail to appear on this list, if the influence is spread among several works. For example, here are the ten most-cited authors who have no individual works represented among the top 253:

John Hawthorne (97 total citations)
Jonathan Bennett (83)
William Alston (77)
Judith Jarvis Thomson (72)
William G. Lycan (71)
Nicholas Rescher (71)
Peter Singer (71)
Ernest Sosa (69)
Jeremy Waldron (68)
Joel Feinberg (67)
Amartya Sen (67)

All of the above are among the top 86 most-cited authors born since 1900. So of course no negative inference about the importance of any individual author is justified by the absence that author's individual works from the works list.

What Percentage of an Author's Citations Are to Their Most-Cited Work?

By comparing my most-cited authors list with my most-cited works list, we can get a rough measure of how much an author's impact is concentrated in a single work vs. spread across multiple works. (Note that the lists are not quite comparable, since the authors list includes only authors born 1900 or later while the works list includes all works published 1900 or later, including works by authors born before 1900.)

Consider, for example, Thomas Kuhn. His Structure of Scientific Revolutions was one of the most influential works of philosophy of the second half of the 20th century. Fittingly, it appears 9th on my list of most influential works. But Kuhn himself appears relatively low on the list of most influential authors: 63rd. Looking at the raw numbers, we can see that 58 entries cite Structure and 71 entries cite any work by Kuhn. Thus, 82% of the Kuhn-citing entries cite Structure.

Contrast this with, say, David Lewis, who is the #1 most-cited contemporary author overall (with 307 entries citing his work) and whose most-cited work, On The Plurality of Worlds, ranks #6 (70 citing entries). For Lewis, 23% (70/307) of the entries that cite him cite his most-cited work.

I can't seem to think of a good name for this number, so I'll have to settle with a bad name: the concentration percentage. Here are the concentration percentages of the ten most-cited contemporary authors in the SEP:

1. Lewis, David K.: 23% (70/307)
2. Quine, Willard van Orman: 32% (69/213)
3. Putnam, Hilary: 24% (45/190)
4. Rawls, John: 76% (127/168)
5. Kripke, Saul A.: 58% (92/159)
6. Williamson, Timothy: 32% (48/152)
7. Davidson, Donald: 21% (31/151)
8. Williams, Bernard: 22% (32/146)
9. Nussbaum, Martha C.: 19% (26/140)
10. Nagel, Thomas: 24% (33/137)

Thus, we can see two clusters: A couple of authors had most of their citation impact through a single work: Rawls (via A Theory of Justice) and Kripke (via Naming and Necessity). The remaining authors had about a third to a fifth of their citation impact through a single work.

Among the top hundred authors, the ten most concentrated are:

Kuhn, Thomas S. (82%: Structure of Scientific Revolutions)
Rawls, John (76%: A Theory of Justice)
Parfit, Derek (71%: Reasons and Persons)
Scanlon, Thomas M. (66%: What We Owe to Each Other)
Kaplan, David (65%: Demonstratives)
Ryle, Gilbert (61%: The Concept of Mind)
Kripke, Saul A. (58%: Naming and Necessity)
Ayer, Alfred J. (54%: Language, Truth, and Logic)
Nozick, Robert (53%: Anarchy, State, and Utopia)
Evans, Gareth (53%: Varieties of Reference)

I confess to being surprised that some of these percentages aren't even higher. For example, I'd have guessed Ryle's impact was more than 61% concentrated on The Concept of Mind.

The ten least concentrated are:

Bennett, Jonathan (16%)
Pettit, Philip (16%)
Harman, Gilbert H. (16%)
Hawthorne, John (15%)
Thomson, Judith Jarvis (15%)
Lowe, E. J. (15%)
Waldron, Jeremy (15%)
Feinberg, Joel (13%)
Yablo, Stephen (13%)
Rescher, Nicholas (6%)

I'll venture a prediction. According to the phenomenon I've labeled "The Winnowing of Greats", the greater your distance from a group that varies in eminence, the greater the difference seems between the most eminent members of that group and the less eminent members. (This is to some extent because you have zero knowledge of most members below a certain level of eminence and to some extent because you overrely on second-hand summaries that highlight a few of the most eminent examples.) If this winnowing phenomenon applies to works as well as to authors, then as time creates distance from our era, all but the most influential works will largely be forgotten -- which will disproportionately favor highly concentrated authors in the historical memory.

[click image to enlarge and clarify]

The Gender and Race/Ethnicity of Authors of the Most-Cited Works of Mainstream Anglophone Philosophy

As is well-known, mainstream Anglophone philosophy has tended to be overwhelmingly non-Hispanic White -- though there's some evidence of recent changes in the student population which might start to trickle into the professoriate. Generally, the higher the level of prestige, the more skewed the ratios. In my 2024 analysis of the 376 most-cited authors in the Stanford Encyclopedia of Philosophy, I found that women or nonbinary authors constituted 12% of the list and Hispanic or non-White authors constituted 3%.

How well represented are these groups among authors of the 253 most-cited works in the Stanford Encyclopedia? Here, the skew is even more extreme. Of the 265 included work-author combinations (almost all of the included works are solo-authored), I count 24 works (9%) by women, 2 (1%) non-binary authored works (both by Judith Butler), one (0.4%) by a Hispanic/Latino person (Linda Martín Alcoff), one (0.4%) by an Asian (Jaegwon Kim), and none by any authors that are known by me to identify or be perceived as Black or African American, American Indian / Alaska Native, or Native Hawaiian or Other Pacific Islander (using the race/ethnicity categories of the US Census). Corrections welcome if I'm misclassified anyone!

Here it is as a pie chart. If you squint, you might be able to see the lines for the Hispanic or non-White groups.

[pie chart comparing 236 non-Hispanic White men with 25 non-Hispanic White women or nonbinary, 1 Hispanic or non-White man, and 1 Hispanic or non-White woman or nonbinary]

The 253 Most Cited Works in the Stanford Encyclopedia of Philosophy

Last summer, Jordan Jackson and I scraped the bibliographies of all the main-page entries of the Stanford Encyclopedia of Philosophy, the leading source of review articles in mainstream Anglophone philosophy. Since 2010, I've been analyzing citation patterns in the SEP. Generally, I find SEP citation rates to more plausibly measure influence in mainstream Anglophone philosophy than other bibliometric measures, such those derived from Web of Science or Google Scholar. (For example, by the SEP method the top five most cited philosophers born 1900 or later are David Lewis, W.V.O. Quine, Hilary Putnam, John Rawls, and Saul Kripke.)

Most of my SEP-based analyses aggregate by author, but it's also revealing to aggregate by work cited, for a couple of reasons. First, my author-based analyses probably overstate the influence of authors with moderate impact across many fields compared to authors with transformative impact in just one or a few fields. Second, tracking influential works is an interesting project in its own right.

Before proceeding to the list, notes and caveats.

(1.) Each work counts once per main-page bibliographic entry in the SEP. Thus, a work with a total of 33 is cited in 33 different main page entries. Subpage entries are not included.

(2.) What counts as the "same work"? The distinction admits vague and contentious cases, and implementing it mechanically raises further problems. Here's what I did: To count as the same work, the work had to begin with exactly the same title words (excluding punctuation marks, "a", "an", or "the"). Later editions were counted as the same work as earlier editions (including a few cases of "such-and-such revisited" or the like) and articles republished in collections were counted as the same work if the particular article rather than the collection as a whole was cited. Also, works that appeared first as articles then later were expanded into books with the same or similar title were counted as the same work. Multi-volume works counted as the same work, unless the title was "Complete Works" or similar.

(3.) I only included works with publication dates from 1900-2024. Older works tend not to be cited in a consistent, easily scraped format, so results for those works are inaccurate and potentially misleading.

(4.) I did not attempt to match works cited both in English and in their original language. Some translated works make the list simply in virtue of citation under their English-language title; and some untranslated works make the list simply in virtue of citation under their original-language title. Obviously, this systematically undercounts works that are cited under both their English and original-language titles.

(4.) Citations in the role of editor are not included.

(5.) Please excuse the haphazard cut-and-paste formatting. Dates are sometimes first appearance, sometimes later appearance or edition or translation.

(6.) Technical details: The matching algorithm looked for matches in the first four letters of the author's name and the first five letters of the first text appearing after numbers, punctuation marks, "the", "an", or "a", which for standardly formatted entries is the title. I then alphabetically sorted and hand-checked all bibliographic lines with at least 15 exact matches of both of the two parameters. This took several hours and was probably imperfect, but was not as difficult as it might seem. Note also: The scrape was conducted last summer, so recent entries and recent updates won't figure into the totals.

(7.) Corrections welcome, as long as they are consistent with the principles above and don't constitute a general revision, unsystematically applied on one author's behalf, of the method described in the technical details.

(8.) I'll follow up, probably in the next week or two, with some reflections on the list.

(9.) You can see the 2020 results here.

ETA Apr 9: Two follow-up posts:

The Gender and Race/Ethnicity of Authors of the Most-Cited Works of Mainstream Anglophone Philosophy (Mar 31)

Further Reflections on the Most-Cited Works in the Stanford Encyclopedia of Philosophy: Underranked Works and Concentration Percentage (Apr 8)

[cover of Rawls's A Theory of Justice]

1. (127 citing entries) Rawls, John, 1971, A Theory of Justice
2. (92) Kripke, Saul, 1972, Naming and Necessity
3. (79) Parfit, Derek, 1984, Reasons and Persons
4. (72) Nozick, Robert, 1974, Anarchy, State, and Utopia
5. (71) Wittgenstein, Ludwig, 1953 [2001], Philosophical Investigations
6. (70) Lewis, David, 1986, On the Plurality of Worlds
7. (69) Quine, W. V. O., 1960. Word and Object
8. (67) Scanlon, T. M., 1998, What We Owe to Each Other
9. (58) Kuhn, Thomas S., 1962, The Structure of Scientific Revolutions
10. (57) Rawls, John, 1996, Political Liberalism
11. (54) Chalmers, David J., 1996, The Conscious Mind
12. (49) Russell, Betrand, 1903, The Principles of Mathematics
13. (48) Lewis, David, 1973. Counterfactuals
13. (48) Sidgwick, Henry, 1907, The Methods of Ethics
13. (48) Williamson, Timothy, 2000, Knowledge and its Limits
16. (47) Kaplan, David, 1977, Demonstratives
16. (47) Moore, G.E., 1903, Principia Ethica
18. (45) Putnam, Hilary, 1975, The Meaning of "Meaning"
18. (45) Quine, W.V.O., 1951, Two Dogmas of Empiricism
20. (43) Jackson, Frank, 1998, From Metaphysics to Ethics
21. (41) Ayer, A.J., 1936, Language, Truth and Logic
22. (39) Carnap, Rudolf, 1956, Meaning and necessity
22. (39) Ross, W.D., 1931, The Right and the Good
22. (39) Ryle, Gilbert, 1949. The Concept of Mind
22. (39) van Fraassen, Bas C., 1980, The Scientific Image
26. (37) Dummett, Michael, 1973, Frege: Philosophy of Language
26. (37) Evans, Gareth, 1982, The Varieties of Reference
26. (37) Mackie, J. L., 1977, Ethics: Inventing Right and Wrong
26. (37) Russell, Bertrand, 1905, On Denoting
26. (37) Whitehead, Alfred North and Bertrand Russell, 1910-1913, Principia Mathematica
31. (36) Goodman, Nelson, 1954. Fact, Fiction and Forecast
32. (35) Popper, Karl R., 1959, The Logic of Scientific Discovery
32. (35) Wittgenstein, L., 1922, Tractatus Logico-Philosophicus
34. (34) Fodor, Jerry A., 1987, Psychosemantics
34. (34) Korsgaard, Christine M., 1996, Sources of Normativity
34. (34) Lewis, David K., 1969, Convention: A Philosophical Study
34. (34) Nozick, Robert, 1981, Philosophical Explanations
34. (34) Raz, Joseph, 1986, The Morality of Freedom
34. (34) Woodward, James, 2003, Making Things Happen
40. (33) Gauthier, David, 1986, Morals by Agreement
40. (33) McDowell, John, 1994, Mind and World
40. (33) Nagel, Thomas, 1986, The View from Nowhere
40. (33) Russell, Bertrand, 1912, The Problems of Philosophy
44. (32) Parfit, Derek, 2017, On What Matters
44. (32) Williams, Bernard, 1985, Ethics and the Limits of Philosophy
46. (31) Davidson, Donald, 1980, Essays on Actions and Events
46. (31) Gibbard, Allan, 1990, Wise Choices, Apt Feelings
46. (31) Strawson, P.F., 1959. Individuals
49. (29) Finnis, John. M, 1980, Natural Law and Natural Rights
49. (29) Fricker, Miranda, 2007, Epistemic Injustice
49. (29) Longino, Helen E., 1990, Science as Social Knowledge
52. (28) Anscombe, G. E. M., 1957, Intention
52. (28) Brandom, Robert B., 1994, Making It Explicit
52. (28) Jackson, Frank, 1982, Epiphenomenal Qualia
52. (28) Pearl, Judea, 2000, Causality: Models, Reasoning, and Inference
52. (28) Plantinga, Alvin, 1974, The Nature of Necessity
52. (28) Quine, W. V. O., 1948, On What There Is
52. (28) Rawls, John, 2001, Justice as Fairness: A Restatement
52. (28) Sellars, Wilfrid, 1956, Empiricism and the philosophy of mind
52. (28) van Inwagen, Peter, 1990, Material Beings
61. (27) Armstrong, David M., 1997, A World of States of Affairs
61. (27) Butler, Judith, 1990, Gender Trouble
61. (27) Dennett, Daniel C., 1991, Consciousness Explained
61. (27) Dretske, Fred I., 1981, Knowledge and the Flow of Information
61. (27) Hare, R.M., 1952, The Language of Morals
61. (27) Lewis, David, 1983, New Work for a Theory of Universals
61. (27) Millikan, Ruth Garrett, 1984, Language, Thought, and Other Biological Categories
61. (27) Nagel, Thomas, 1974, What is It Like to Be a Bat?
61. (27) Smith, Michael, 1994, The Moral Problem
61. (27) Young, Iris Marion, 1990, Justice and the Politics of Difference
71. (26) Carnap, Rudolf, 1950, Logical Foundations of Probability
71. (26) Frankfurt, Harry, 1971, Freedom of the Will and the Concept of a Person
71. (26) Grice, Herbert Paul, 1989, Studies in the Way of Words
71. (26) Jeffrey, Richard C., 1965 [1983], The Logic of Decision
71. (26) Kripke, Saul, 1982, Wittgenstein on Rules and Private Language
71. (26) Nussbaum, Martha C., 2006, Frontiers of Justice
71. (26) Searle, John R., 1983, Intentionality
78. (25) Anderson, Elizabeth S., 1999, What Is the Point of Equality?
78. (25) Armstrong, David M., 1968, A Materialist Theory of Mind
78. (25) Dworkin, Ronald, 1977, Taking Rights Seriously
78. (25) Fodor, Jerry A., 1975, The Language of Thought
78. (25) Hart, H.L.A., 1961, The Concept of Law
78. (25) Hempel, Carl G., 1965, Aspects of Scientific Explanation
78. (25) Kneale, William and Martha Kneale, 1962. The Development of Logic
78. (25) MacIntyre, Alasdair, 1984. After Virtue
78. (25) Nagel, Ernest, 1961, The Structure of Science
78. (25) Ramsey, Frank P., 1931, Truth and Probability
78. (25) Rawls, John, 1999, The Law of Peoples
78. (25) Russell, Bertrand, 1918/1919, The Philosophy of Logical Atomism
78. (25) Stalnaker, Robert, 1984, Inquiry
78. (25) Williamson, Timothy, 2007, The Philosophy of Philosophy
92. (24) Blackburn, Simon, 1998, Ruling Passions
92. (24) Brink, David O., 1989. Moral Realism and the Foundations of Ethics
92. (24) Burge, Tyler, 1979, Individualism and the Mental
92. (24) Dupré, John, 1993, The Disorder of Things
92. (24) Fine, Kit, 1994, Essence and Modality
92. (24) Hare, R.M., 1981, Moral Thinking
92. (24) Lewis, D., 1986, Philosophical Papers
92. (24) Quine, W. V. O., 1970, Philosophy of Logic
100. (23) Carnap, Rudolf, 1950, Empiricism, Semantics, and Ontology
100. (23) Cartwright, Nancy, 1983, How the laws of physics lie
100. (23) Gilligan, Carol, 1982, In a Different Voice
100. (23) Griffin, James, 1986, Well-Being: its Meaning, Measurement, and Moral Importance
100. (23) Kitcher, Philip, 1993, The Advancement of Science
100. (23) Putnam, Hilary, 1981, Reason, Truth and History
100. (23) Savage, Leonard J., 1954, The Foundations of Statistics
100. (23) Searle, John R., 1969, Speech Acts
100. (23) Shafer-Landau, Russ, 2005, Moral Realism
100. (23) Spirtes, Peter, Clark Glymour, and Richard Scheines, 1993, Causation, Prediction, and Search
100. (23) Stalnaker, Robert C., 1968, A Theory of Conditionals
100. (23) Turing, Alan M., 1936 [1965], On Computable Numbers, with an Application to the Entscheidungsproblem
112. (22) Davidson, Donald, 1963. Actions, Reasons, Causes
112. (22) Dretske, Fred, 1995, Naturalizing the Mind
112. (22) Fodor, Jerry A., 1983, Modularity of Mind
112. (22) Machamer, Peter, Lindley Darden, and Carl F. Craver, 2000, Thinking about Mechanisms
112. (22) Street, Sharon, 2006, A Darwinian Dilemma for Realist Theories of Value
112. (22) van Fraassen, Bas C., 1989, Laws and Symmetry
112. (22) Zalta, Edward N., 1983, Abstract Objects
119. (21) Alcoff, Linda Martin, 2006. Visible Identities
119. (21) Brandt, Richard B., 1979, A Theory of the Good and the Right
119. (21) Cartwright, Nancy, 1999, The Dappled World
119. (21) Dawkins, Richard, 1976, The Selfish Gene
119. (21) Dworkin, Ronald, 1986, Law's Empire,
119. (21) Field, Hartry, 1989, Realism, Mathematics and Modality
119. (21) Fodor, Jerry A., 1974, Special Sciences (or: The Disunity of Science as a Working Hypothesis)
119. (21) Gettier, Edmund L., 1963, Is Justified True Belief Knowledge?
119. (21) Longino, H. 2001, The Fate of Knowledge
119. (21) Nussbaum, Martha C., 2000. Women and Human Development
119. (21) Okin, Susan Moller, 1989, Justice, Gender, and the Family
119. (21) Sober, Elliott and David Wilson, 1998, Unto Others
119. (21) Strawson, Peter F., 1962, Freedom and Resentment
119. (21) Tye, Michael, 1995, Ten Problems of Consciousness
119. (21) Walzer, Michael, 1983, Spheres of Justice
119. (21) Wiggins, David, 1980, Sameness and Substance
135. (20) Austin, J.L., 1962, How to Do Things with Words
135. (20) Chisholm, Roderick M., 1957, Perceiving
135. (20) Dancy, Jonathan, 2004, Ethics Without Principles
135. (20) Darwall, Stephen, 2006. The Second-Person Standpoint
135. (20) Davidson, Donald, 1984, Inquiries into truth and interpretation
135. (20) Dennett, Daniel C., 1987, The Intentional Stance
135. (20) Dworkin, Ronald, 2000. Sovereign Virtue
135. (20) Feyerabend, Paul K., 1975, Against Method
135. (20) Gödel, Kurt, 1931, Über formal unentscheidbare Sätze der Principia Mathematica und verwandter Systeme I
135. (20) Husserl, Edmund, 1900-01, Logische Untersuchungen
135. (20) Quine, Willard Van Orman, 1953, From A Logical Point of View
135. (20) Reichenbach, Hans, 1938, Experience and Prediction
135. (20) Rorty, Richard, 1979, Philosophy and the Mirror of Nature
135. (20) Rosen, Gideon, 2010, Metaphysical Dependence
135. (20) Wright, Crispin, 1983, Frege's Conception of Numbers as Objects
135. (20) Zalta, Edward N., 1988, Intensional Logic and the Metaphysics of Intentionality
151. (19) Anderson, Alan and Nuel Belnap, 1975, Entailment: The logic of relevance and necessity
151. (19) Blackburn, Simon, 1984. Spreading the Word
151. (19) Blackburn, Simon, 1993, Essays in Quasi-Realism
151. (19) Chisholm, Roderick M., 1976, Person and Object
151. (19) Craver, Carl F., 2007, Explaining the Brain
151. (19) Fischer, John Martin and Ravizza, Mark, 1998. Responsibility and Control
151. (19) Grice, H. P., 1975, Logic and Conversation
151. (19) Hintikka, Jaakko, 1962, Knowledge and Belief
151. (19) Keynes, John Maynard, 1921, A Treatise on Probability
151. (19) Lewis, David, 1979, Attitudes De Dicto and De Se
151. (19) Parsons, Terence, 1980, Nonexistent Objects
151. (19) Pogge, Thomas, 2002 [2008], World Poverty and Human Rights
151. (19) Priest, Graham, 1987, In Contradiction
151. (19) Salmon, Nathan, 1986, Frege's Puzzle
151. (19) Sider, Theodore, 2001, Four-Dimensionalism
151. (19) Tarski, A., 1983, Logic, Semantics, Metamathematics
151. (19) Thomasson, Amie L., 1999, Fiction and Metaphysics
151. (19) Williamson, Timothy, 2013. Modal Logic as Metaphysics
169. (18) Armstrong, D., 1989, Universals: An Opinionated Introduction
169. (18) Barnes, Jonathan, 1982, The Presocratic Philosophers
169. (18) Chisholm, Roderick M., 1966, Theory of Knowledge
169. (18) Fodor, J., 1992, A Theory of Content and Other Essays
169. (18) Gibbard, Allan, 2003, Thinking How to Live
169. (18) Goodman, Nelson, 1968, Languages of Art
169. (18) Hacking, Ian, 1983, Representing and Intervening
169. (18) Harman, Gilbert, 1986, Change in View
169. (18) Hilbert, David and Wilhelm Ackermann, 1928, Grundzüge der Theoretischen Logik
169. (18) Kahneman, Daniel, 2011, Thinking, Fast and Slow
169. (18) Kittay, Eva Feder, 1999, Love's Labor
169. (18) Lewis, David K., 1991, Parts of Classes
169. (18) Lewis, David, 1973, Causation
169. (18) Moore, G. E., 1912. Ethics
169. (18) Noë, Alva, 2004, Action in Perception
169. (18) Prior, Arthur N., 1967, Past, Present and Future
169. (18) Salmon, Wesley, 1984, Scientific Explanation and the Causal Structure of the World
169. (18) Schaffer, Jonathan, 2009, On What Grounds What
169. (18) Searle, John R., 1992, The Rediscovery of the Mind
169. (18) Stich, Stephen P., 1983, From folk psychology to cognitive science
169. (18) Taylor, Charles, 1989, Sources of the Self
169. (18) Walton, Kendall, 1990, Mimesis as Make-Believe
169. (18) Wright, Crispin, 1992, Truth and Objectivity
192. (17) Annas, Julia, 1993, The Morality of Happiness
192. (17) Anscombe, G.E.M., 1958, Modern Moral Philosophy
192. (17) Benacerraf, Paul, 1973, Mathematical Truth
192. (17) Carnap, Rudolf, 1928. Der logische Aufbau der Welt
192. (17) Davidson, Donald, 1970, Mental Events
192. (17) Dretske, Fred, 1988, Explaining behavior
192. (17) Field, Hartry, 1980, Science Without Numbers
192. (17) Goldman, Alvin, 1979, What is Justified Belief?
192. (17) Graham, Angus C., 1989, Disputers of the Tao
192. (17) Grice, H. P., 1957, Meaning
192. (17) Guthrie, W.K.C., 1962-1981, A History of Greek Philosophy
192. (17) Hooker, Brad, 2000, Ideal Code, Real World
192. (17) Howson, Colin and Peter Urbach, 2006, Scientific Reasoning
192. (17) Hull, David L., 1988, Science as a Process
192. (17) Kagan, Shelly, 1989, The Limits of Morality
192. (17) Kim, Jaegwon, 1998, Mind in a Physical World
192. (17) Kleene, Stephen Cole, 1952, Introduction to Metamathematics
192. (17) Lewis, David, 1980, A Subjectivist's Guide to Objective Chance
192. (17) List, Christian and Philip Pettit, 2011, Group Agency
192. (17) MacKinnon, Catherine, 1989, Towards a Feminist Theory of the State
192. (17) Marr, David, 1982, Vision
192. (17) Peacocke, Christopher, 1992, A Study of Concepts
192. (17) Plantinga, Alvin, 2000, Warranted Christian Belief
192. (17) Ross, W.D., 1939, Foundations of Ethics
192. (17) Russell, B., 1914, Our Knowledge of the External World
192. (17) Schneewind, J. B., 1998. The Invention of Autonomy
192. (17) Tarski, Alfred, 1935, The Concept of Truth in Formalized Languages
192. (17) van Inwagen, Peter, 1983. An Essay on Free Will
192. (17) Von Neumann, John and Oskar Morgenstern, 1944, Theory of Games and Economic Behavior
221. (16) Adams, Robert Merrihew, 1994, Leibniz
221. (16) Armstrong, D. M., 1978, Universals and Scientific Realism
221. (16) Axelrod, Robert and William D. Hamilton, 1981, The Evolution of Cooperation
221. (16) Butler, Judith, 1993. Bodies That Matter
221. (16) Churchland, Paul M., 1981, Eliminative materialism and the propositional attitudes
221. (16) Clark, Andy and David J. Chalmers, 1998, The Extended Mind
221. (16) Dummett, Michael, 1991, The Logical Basis of Metaphysics
221. (16) Fine, Kit, 2001, The Question of Realism
221. (16) Frankfurt, Harry, 1988. The Importance of What We Care About
221. (16) Frege, Gottlob, 1918/1956, The Thought: A Logical Inquiry
221. (16) Geach, Peter, 1962, Reference and Generality
221. (16) Gödel, Kurt, 1944, Russell's Mathematical Logic
221. (16) Hare, R. M., 1963. Freedom and Reason
221. (16) Horgan, Terence and John Tienson, 2002, The Intentionality of Phenomenology and the Phenomenology of Intentionality
221. (16) Irwin, Terence. H., 2008, The Development of Ethics
221. (16) Joyce, James M., 1999, The Foundations of Causal Decision Theory
221. (16) Kane, Robert, 1996, The Significance of Free Will
221. (16) Lipton, Peter, 1971 [2003], Inference to the Best Explanation
221. (16) Lloyd, Genevieve, 1984, The Man of Reason
221. (16) McMahan, Jeff, 2002, The Ethics of Killing
221. (16) Mellor, D.H., 1981, Real Time
221. (16) Perry, John, 1979, The Problem of the Essential Indexical
221. (16) Popper, Karl, 1962. Conjectures and refutations
221. (16) Raz, J., 1990. Practical reason and norms
221. (16) Russell, Bertrand, 1927, The Analysis of Matter
221. (16) Sandel, Michael J., 1982. Liberalism and the Limits of Justice
221. (16) Scheffler, Samuel, 1982, The Rejection of Consequentialism
221. (16) Stalnaker, Robert, 1978, Assertion
221. (16) Stevenson, Charles L., 1944, Ethics and Language
221. (16) Swinburne, Richard, 1977, The Coherence of Theism
221. (16) Tye, Michael, 2000, Consciousness, Color, and Content
221. (16) Williams, Bernard, 1981, Moral Luck
221. (16) Williams, George C., 1966, Adaptation and Natural Selection