Revisiting my Dissertation

Nine years ago I defended My dissertation and then I promptly forgot about it. Part of the reason was that I was distracted with the Shombie Wars (believe me, I *never* expected to write a paper on zombies!) and starting Consciousness Online but the biggest part of the story was that I was sick of working on it. I had spent two years writing it officially but I had had the core idea for the dissertation in 2002 (developing ideas I had from my days as an undergraduate) and had written several versions of it for various seminars I had taken. By the time I had decided to pursue this as my dissertation project I had already been working on it (off and on) for 4 years. So after six years of reading, re-reading, writing, and re-writing I had a hard time even thinking about this material!

Looking back on it now I think the main “result” still stands up. Just after I defended hybrid expressionist views became popular and I thought that maybe I had been scooped  (more than I already had been by Blackstone!) but no one has developed, or even seemed to notice, the kind of hybrid view I formulate and defined (i.e. one where the speech act in moral discourse involves expressing an emotion and, at the same time, the belief that the emotion is the correct one to have towards the relevant state of affairs moral character, etc)…though to be honest I have grown more out of touch with the literature on metaethics…so maybe there is some devastating objection I am not aware of?

At some point I may try to look into it but in the meantime below are links to the blog posts I wrote while working on the dissertation.

  1. Introducing Frigidity
  2. What Kripke Really Thinks
  3. The Meaning and Use of ‘is True’
  4. Truth, Justification, and the Quasi-Realist Way
  5. Meaning and Justification
  6. A Simple Argument for Moral Realism
  7. Emotive Realism
  8. Truth and Necessity
  9. Varieties of Rigidity
  10. Devitt on the A Priori 
  11. Meta-Metaethics and the NJRPA
  12. Emotive Realism Ch. 1
  13. Emotive Realism Ch. 2
  14. Some Moral Truths are Analytic
  15. (Finally) Responding to Roman
  16. Moral Truthmakers
  17. Empiricism as the Default Position
  18.  Introducing Dr. Richard Brown

Papers I almost Wrote

In celebration of my ten years of blogging I have been collecting some of my posts into thematic meta-posts. The previous two listed my writing on the higher-order thought theory of consciousness and my writing about various conferences and classes I have attended. Continuing in that theme below are links to posts I have written about various things that are not in either of the two previous categories. Some of these I had thought I might develop into papers or something but so far that hasn’t happened!

  1. Freedom and Evil
    • This was written for a debate at Brooklyn College entitled ‘If there is a God, Why does Evil Exist?” sponsored by the InterVarsity Christian Fellowship
  2. There is No Santa
    • Is it wrong to lie to children about the existence of Santa? I think so!
  3. What’s So Unobservable about Causation?
    • This is an excerpt from a paper I wrote while a graduate student at the University of Connecticut
  4. Freedom of Speech Meets Speech Act Theory
    • Freedom of speech means freedom of assertion but not the freedom to perform any speech act one wants
  5. Reason and The Nature of Obligation
    • A discussion of Locke and Hobbes on reason and obligation. I think this was first written for a class I had on social and political philosophy. I argue that both are committed to the view that reason is the source of moral obligation but fear (or some external motivator) is required to get people to conform to reason.
  6. Logic, Language, and Existence
    • I discover the problem of necessary existence, and, as usual, also discover that I have reinvented (a crappier version of) the wheel
  7. Timothy Williamson on Necessary Existents
  8. Stop your Quining!!!
    • Are there any counter-examples to some common analytic truths? I don’t think so
  9. What God Doesn’t Know
    • Can we invent Liar Paradox-type sentences involving God’s knowledge? Spoiler alert: yes!
  10. A Counter-Example to the Cogito?
    • Are you nothing more than an alternate personality of the all-power Evil Genius?
  11. Conceptual Atomism, Functionalism, and the Representational Theory of Mind
    • Can we construct quaility-inversion-type scenarios for the mental attitudes? I give it my best shot.
  12. Did Quine Change His Mind?
    • No he did not. The axioms of logic are revisable but we haven’t got any good reason to revise them (yet)
  13. God v. the Delayed Choice Quantum Eraser
    • one of my most popular posts.
  14. The Evolutionary Argument against Rationalism
    • Evolution may have built certain facts about our local reality into the brain, thus generating a priori justification (of a sort)
  15. The A Priori Argument against Rationalism
    • Is it conceivable that there are no necessary truths?
  16. The Empirical Justification of Mathematics
    • Could there be empirical disconfirmation of basic arithmetic?
  17. Invoking God Doesn’t Save Descartes from Skepticism
    • Doesn’t the case of Job from the bible undermine Descartes’ claim that God is not a deceiver?
  18. The (New) Agnostic’s Manifesto: Part 1 –Preamble
  19. Secular Ethics vs. Religious Ethics
  20. Breaking Promises
    • When is a promise broken versus excused?
  21. Second Thoughts about Pain Asymbolia
  22. Transworld Saints
  23. The Logical Problem of Omniscience
  24. Empiricism and A Priori Justification
  25. Reduction v. Elimination
  26. Why I am not a Type-Z Materialist
  27. Pain Asymbolia and a Priori Defeasibility
  28. Summa Contra Plantinga
  29. The Unintelligibility of Substance Dualism
  30. What is Philosophy that it Sucks so Bad?
  31. Identifying the Identity Theory
  32. Can we think about Non-Existant Objects?
  33. The Zombie Argument Depends on Phenomenal Transparency
  34. Bennett on Non-Reductive Physicalism
  35. News Flash: Philosophy Sucks!
  36. Kant’s response to Hume’s Challenge in Ethics
  37. The Identity Theory in 2-D
  38. Outline of the Case for Agnosticism
  39. Consciousness Studies in 100 words (more) or less
  40. The Argument from Photosynthesis
    • Could humans be photosynthetic? The answer seems to be yes and this i bad news for the problem of evil
  41. The Design Argument for the Simulation Hypothesis
  42. Consciousness as an M-Property (?)
  43. If Consciousness is an M-Property then it is Physical
  44. Do We Live in a Westworld World??
  45. Eliminativism and the Neuroscience of Consciousness

Dispatches from the Ivory Tower

In celebration of my ten years in the blogosphere I have been compiling some of my past posts into thematic meta-posts. The first of these listed my posts on the higher-order thought theory of consciousness. Continuing in this theme below are links to posts I have done over the past ten years reporting on talks/conferences/classes I have attended. I wrote these mostly so that I would not forget about these sessions but they may be interesting to others as well. Sadly, there are several things I have been to in the last year or so that I have not had the tim to sit down and write about…ah well maybe some day!

  1. 09/05/07 Kripke
    • Notes on Kripke’s discussion of existence as a predicate and fiction
  2. 09/05/2007 Devitt
  3. 09/05 Devitt II
  4. 09/19/07 -Devitt on Meaning
    • Notes on Devitt’s class on semantics
  5. Flamming LIPS!
  6. Back to the Grind & Meta-Metaethics
  7. Day Two of the Yale/UConn Conference
  8. Peter Singer on Climate Change and Ethics
    • Notes on Singer’s talk at LaGuardia
  9. Where Am I?
    • Reflections on my talk at the American Philosophical Association talk in 2008
  10. Fodor on Natural Selection
    • Reflections on the Society of Philosophy and Psychology meeting June 2008
  11. Kripke’s Argument Against 4-Dimensionalism
    • Based on a class given at the Graduate Center
  12. Reflections on Zoombies and Shombies Or: After the Showdown at the APA
    • Reflections on my session at the American Philosophical Association in 2009
  13. Kripke on the Structure of Possible Worlds
    • Notes on a talk given at the Graduate Center in September 2009
  14. Unconscious Trait Inferences
    • Notes on social psychologist James Uleman‘s talk at the CUNY Cogsci Speaker Series September 2009
  15. Attributing Mental States
    • Notes on James Dow‘s talk at the CUNY Cogsci Speaker Series September 2009
  16. Busy Bees Busily Buzzing ‘Bout
  17. Shombies & Illuminati
  18. A Couple More Thoughts on Shombies and Illuminati
    • Some reflections after Kati Balog’s presentation at the NYU philosophy of mind discussion group in November 2009
  19. Attention and Mental Paint
    • Notes on Ned Block’s session at the Mind and Language Seminar in January 2010
  20. HOT Damn it’s a HO Down-Showdown
    • Notes on David Rosenthal’s session at the NYU Mind and Language Seminar in March 2010
  21. The Identity Theory in 2-D
    • Some thoughts in response to theOnline Consciousness Conference in February 2010
  22. Part-Time Zombies
    • Reflections on Michael Pauen‘s Cogsci talk at CUNY in March of 2010
  23. The Singularity, Again
    • Reflections on David Chalmers’ at the NYU Mind and Language seminar in April of 2010
  24. The New New Dualism
  25. Dream a Little Dream
    • Reflections on Miguel Angel Sebastian’s cogsci talk in July of 2010
  26. Explaining Consciousness & Its Consequences
    • Reflections on my talk at the CUNY Cog Sci Speaker Series August 2010
  27. Levine on the Phenomenology of Thought
    • Reflections on Levine’s talk at the Graduate Center in September 2010
  28. Swamp Thing About Mary
    • Reflections on Pete Mandik’s Cogsci talk at CUNY in October 2010
  29. Burge on the Origins of Perception
    • Reflections on a workshop on the predicative structure of experience sponsored by the New York Consciousness Project in October of 2010
  30. Phenomenally HOT
    • Reflections on the first session of Ned Block and David Carmel’s seminar on Conceptual and Empirical Issues about Perception, Attention and Consciousness at NYU January 2011
  31. Some Thoughts About Color
  32. Stazicker on Attention and Mental Paint
  33. Sid Kouider on Partial Awareness
    • a few notes about Sid Kouider’s recent presentation at the CUNY CogSci Colloquium in October 2011
  34. The 2D Argument Against Non-Materialism
    • Reflections on my Tucson Talk in April 2012
  35. Peter Godfrey-Smith on Evolution And Memory
    • Notes from the CUNY Cog Sci Speaker Series in September 2012
  36. The Nature of Phenomenal Consciousness
    • Reflections on my talk at the Graduate Center in September 2012
  37. Giulio Tononi on Consciousness as Integrated Information
    • Notes from the inaugural lecture of the new NYU Center for Mind and Brain by Giulio Tononi
  38. Mental Qualities 02/07/13: Cognitive Phenomenology
  39. Mental Qualities 02/21/13: Phenomenal Concepts
    • Notes/Reflections from David Rosenthal’s class in 2013
  40. The Geometrical Structure of Space and Time
    • Reflections on a session of Tim Maudlin’s course I sat in on in February 2014
  41. Towards some Reflections on the Tucson Conferences
    • Reflections on my presentations at the Tucson conferences
  42. Existentialism is a Transhumanism
    • Reflections on the NEH Seminar in Transhumanism and Technohumanism at LaGuardia I co-directed in 2015-2016

Recent Events

Well, the semester at LaGuardia is finally coming to a close (our schedule is out of step with the rest of CUNY). A lot has been going on and I have barely had time to do anything but since today is our reading day and I have a brief break before final exams come in, I thought I would quickly talk about what has been going on.

My new course, Cosmology, Consciousness, and Computation was a huge success and the students really seemed to enjoy the chance to take these kinds of questions seriously. The basic idea behind the course is to explore issues related to physicalism but after a grounding in the actual physics. My experiment to use the Stanford Encyclopedia as a primary text seemed to work ok as well. Some of the readings are fairly technical but I gave students the choice of which to read and which to write a one page summary/reaction to. They also seemed to like the Terminator book, which was nice. This is the first time I have used it in a class. I am toying with the idea of maybe recording the lectures for this course over the summer as I prepare to teach it again next semester (but I am also teaching philosophy of religion and ethics over the summer and I am tempted to record my philosophy of religion as well…they do overlap a bit so maybe I’ll do both!). For those interested, here is the syllabus. As with any new class I expect to update a lot of it in light of what happened this semester and any feedback would be appreciated.

All of that will have to wait until later in July, though, since I am currently getting ready for my trip to San Diego for the 17th meeting of the Association for the Scientific Study of Consciousness (ASSC). This year I have organized a symposium on the Role of the Prefrontal Cortex in Conscious Experience. The speakers are Rafi Malach, Joe Levine, Doby Rahnev, and myself. I am really looking forward to it, as well as to the rest of the program! I am hoping to post a video of my talk in the nearish future.

I have also been working on a new paper, which came out of discussion at the 5th Online Consciousness Conference. It is entitled Consciousness is (Probably) a Biological Phenomenon. Those who know me know that I am attracted to an identity theory when it comes to consciousness and that I harbor the suspicion that consciousness is a uniquely biological phenomenon. This paper is my first attempt to spell out an answer to Chalmers’ fading and dancing qualia arguments using empirical results (in particular the partial report results that have figured in the overflow debate (see here and here)). It is extremely drafty (I have been working on it an hour here and hour there for the last few weeks) and any feedback would be much appreciated.

In addition to all of this I have just returned from my trip to the Omaha Kripke Conference (during which I was also on my first dissertation committee at the Grad Center, which was very much fun but then I also had to read and think about a dissertation!), which was a really rewarding experience. Omaha is a wonderful town and the conference itself was excellent, if exhausting. Three days of excellent papers and excellent discussion, and it was very cool to see Saul so active and engaging with the material. Unfortunately, due to bad weather, he came late and so he missed my talk but there was none the less a lot of very helpful discussion. The main objection was Dan Shargel’s ‘hierarchy objection’ which he presented at Tucson last year (the basic idea is that we can move the argument up to the level of appearance and imagine that we have that appearance without the neural state, etc). I have got to get better at explaining what my answer to that objection is. After the discussion at the conference I have come to think that the main problem is that we are using ‘how pain appears to me’ as a way to pick out two different states, one a psychological state and the other a neural state. On the one hand we use it to pick out the pain sensations, that is the first-order sensing of bodily damage. But we can also use it to pick out the neural state that the appearance is identical to (note: not the neural state that the sensation is identical to, but the neural state that is identical to the awful painfulness appearance. We can use the appearance property as a way to pick out that state itself). It is in that second sense that we avoid the charge of regress. This takes some spelling out to make sense of it and I am hoping to write something more detailed on it in the nearish future (hopefully before I head out to the ASSC).

During and after one of the other sessions I had the chance to talk to Saul about his 1963 paper Semantical Considerations on Modal Logic, which I have discussed previously on the blog. When I suggested that it was a cost to one’s theory to give up logical constants in your quantified modal logic he insisted that it was not. This was because for any sentence with a logical constant in it we could translate it into a sentence without the constant without loss of meaning using Quine’s trick of inventing a predicate. This led me to wonder whether this made it the case that we could reformulate the bothersome proofs using translated sentences. At the time I wasn’t able to come with a way to do this but once I got home I thought about it a bit more and came up with the following.

In the original reductio we used this sentences ☐∃x(x=k), where this is read as ‘there exists an x such that x is identical to Saul Kripke’. How would we translate this sentence to get rid of the constant? We would replace the constant with a predicate, say ‘K’ (‘the Kripisizer’) and thus we would get ☐∃x(x=Ky) but this has a free variable in it so we would have to take it as asserting the ‘closed’ version, so we get ∀y☐∃x(x=Ky). We can then proceed to prove this in the same way as before using a reductio

1. ~∀y☐∃x(x=Ky) -assumption for reductio
2. ∃y~☐∃x(x=Ky) -1, quantifier exchange
3. ∃y◊~∃x(x=Ky) -2, definition of ☐
4. ∃y◊∀x~(x=Ky) -3, quantifier exchange
5. ∃y◊~(Ky=Ky) -Universal instantiation on 4
6. ∀y☐(Ky=Ky) -instance of axiom of identity
7. ~∃y~☐(Ky=Ky) -6, quantifier exchange
8. ~∃y◊~(Ky=Ky) -7, definition of ☐
9. ∃y◊~(Ky=Ky) & ~∃y◊~(Ky=Ky) -4,8 -conjunction introduction
10. ∀y☐∃x(x=Ky) -1-9 reduction

I think the main issue with this reformulated proof is line 5 when I use ‘Ky’ as an instance of x in 4. It seems to me that this move should be allowed, though. This is because part of the whole point of the 1963 paper was that we could block these kinds of proofs and still keep our traditional quantification theory. So we should be able to use UI, but if we are not allowed the use of constants then we will have to use predicates, which is what I did. Also, the variable in 5 is not free and is bound by the existential quantifier. So all in all I think this reformulated proof works but I really haven’t had the time to think about it very carefully.

Well that is enough for now…time to head over to Brains to read some of the commentaries in the Symposium on Louise Richardson’s “Flavor, Taste and Smell”.

Zombies vs Shombies

Richard Marshall, a writer for 3am Magazine, has been interviewing philosophers. After interviewing a long list of distinguished philosophers, including Peter Carruthers, Josh Knobe, Brian Leiter, Alex Rosenberg, Eric Schwitzgebel, Jason Stanley, Alfred Mele, Graham Priest, Kit Fine, Patricia Churchland, Eric Olson, Michael Lynch, Pete Mandik, Eddy Nahmais, J.C. Beal, Sarah Sawyer, Gila Sher, Cecile Fabre, Christine Korsgaard, among others, they seem to be scraping the bottom of the barrel, since they just published my interview. I had a great time engaging in some Existential Psychoanalysis of myself!

Does All Imply Some?

So in the logic course I am currently teaching we are about to start talking about the contrast between the modern and traditional square of opposition. The main difference, of course, is that poor Aristotle thought that if it was true that All A’s are B’s that made it the case that Some particular A was in fact B, and so he would be forced to exclude syllogisms as valid that have fictional terms. Consider the following proposition,

1. Some humans are mammals

Now, I often find that students think that 1 is false. They think that it is false because they think that it implies 2

2. Some humans are not mammals

but in the traditional square of opposition this is not the case. 1 and 2 are subcontraries, which means that they can’t both be false. Now this means that it is a possibility that both of them are true, but there is also the possibility that only one of them is true and the other is false.  Since it is true that all humans are mammals by subalternation we know that 1 is true . Thus, we can say that 1 is true because we know that 3 is true and 2 has to be false because it is the contradiction of 3.

3. All humans are mammals

But what are we to make of this on the modern interpretation? Can we no longer say that 1 is true because of the fact that all humans are mammals? It is still the case that 2 is false, as it is still the contradiction of 1. But what about the so-called existential fallacy?

But if we take this discussion out of the realm of categorical propositions and start talking in terms of truth-functional semantics don’t we get the traditional square back? So, 1 is written as 1* with

1* Ex(Hx & Mx)

Whereas 2 and 3 turns into 2* and  3*

2* Ex(Hx & ~Mx)

3* (x)(Hx–>Mx)

So to get the traditional square back we would need to show that 3* implies 1*.

Consider the following proof,

A. (x) (Hx –>Mx) [assumption]

B.  Ex (Hx) [assumption]

C. Hy [Existential Instantiation of B]

D. Hy –> My [Universal Instantiation of A]

E. My (Modus Ponens D, C)

E. Hy & My [conjunction introduction]

F. Ez (Hz & Mz) [existential generalization]

So, if B is correct and there are humans then 3 does entail 1 just like Aristotle said. Am I missing something?

Zombies and Impossible Worlds

Via Leiter’s blog I happened to be looking at the list of recent SEP entries. I read this entry on impossible worlds that got me thinking.

The response to the zombie argument that I have been developing over the last couple of year appeals to the distinction between prima facie and ideal conceivability. Something is prima facie conceivable, roughly, if there is no obvious contradiction in the imagined scenario. Something is ideally conceivable if, roughly, there is no contradiction in the imagined scenario even upon ideal reflection. I have tried to argue that zombies are merely prima facie conceivable and may not turn out to be ideally conceivable (another way of putting it that is roughly equivalent is that zombies are epistemically possible but not metaphysically possible) since there are equally plausible parity arguments (zoombies and shombies). As a corollary of this line of defense I have argued that what people like Dave actually succeed in imagining when they *think* they imagine the zombie world is really just a world that is very similar to the actual world. Just as a point of clarification I have always meant this to be a different claim than the Russellian response that the zombie world may have different ‘inscrutable’ fundamental physical properties. What I mean is that since we do not yet know all of the facts about the brain, physics, or theories of consciousness, we may be inadvertently failing to include some crucial physical law, property, or theory of consciousness. So it is very easy, I claim, to imagine a world that is physical in roughly the same sense that ours is but where there is no consciousness. For instance, if the higher-order thought theory of consciousness is right then the ‘zombie’ world is really just a world like ours that lacks higher-order thoughts.

Now people like Dave often claim that they can conceive that we add this feature and yet still it is intuitive that those creature could lack consciousness. If this is really the case and the higher-order theory is true then Dave has imagined an impossible world. But it seems to me that we can at this point admit that the traditional zombie world is conceivable and go on to argue for a restriction on the second premise of zombie argument, which to remind us, is the claim that if zombie are conceivable then they are possible. This premise becomes possibly false since it may be the case that zombies are conceivable but not metaphysically possible, where this means that they inhabit an impossible world.

One response to this line of thought might be that the use of ‘conceivability’ here isn’t the same as that employed by the zombie argument. As used by Dave ‘conceivable’ means roughly imaginable without contradiction but in these impossible worlds we conceive of a world with a contradiction (by stipulation it contains a contradiction). But, of course, the point here is that one may not notice or be in a position to spot the contradiction, which is exactly one of the reasons for postulating impossible worlds (or in this case impossible scenarios in Dave’s sense). If one takes this line, as I am inclined to do myself, then the issue reduces to the original one of the difference between prima facie conceivability and ideal conceivability. But if one has a more generic version of conceivability one can argue that zombies are conceivable and impossible in way that seems different from the usual type-b line…

Sellars on Mind and Language

I found this very interesting lecture by Sellars where he talks about dot quotes and its relation to ontology and the mind-body problem…all good stuff and worth a listen. But what really caught my interest was his comments at the beginning of part F where he seems to admit that some kind of causal theory has to be right for the way thoughts work but not for the linguistic meaning…is there any other way to interpret these remarks? Also, does anyone else feel like they are listening to Jimmy Stewart talk about philosophy??


On my way home from class today I realized that what Sellars says in these lectures vindicates something I thought of after someone objected that on my view names would fail the Church translation test. t thought you could just dot quite your way out of it so it is nice to hear Sellars talking about dot quoting ‘Socrates’.

The Terminator and Philosophy: Call for Abstracts

The Terminator and Philosophy

Edited by Richard Brown and Kevin S. Decker

The Blackwell Philosophy and Popular Culture Series

Please circulate and post widely.

Apologies for Cross-posting.

To propose ideas for future volumes in the Blackwell series please contact the Series Editor, William Irwin, at

Abstracts and subsequent essays should be philosophically substantial but accessible, written to engage the intelligent lay reader. Contributors of accepted essays will receive an honorarium.

Possible themes and topics might include, but are not limited to, the following:

“Can We Really Change the Future?” or “Killing Sarah Connor”: Cyberdyne Systems, time travel and the grandfather paradox; Skynet and John Connor: philosophy of technology and creating our own enemies; “Sentience, Sapience, and Self-Awareness”: issues in philosophy of mind; Neural Net to Supercomputer to ‘Software in Cyberspace’: Skynet and multiple realization;“Is Skynet Justified in Defending Itself?” the ethics of war and artificial intelligence; “Irrefutable Delusions”: Sarah Connor, Delusional Beliefs, and Standards of Evidence in T2;“Stop Miles Bennett Dyson”: Sarah Connor’s transformation into a killer (is violence contagious?) or Sarah Connor’s transformation from ‘80’s ditz to Feminist Icon; “Judgment Day is Unavoidable” or “No Fate but what we Make”: eternalist vs. presentist perspectives on the original versus modified timelines; “John Connor is the Most Important Person in the World”: causality and the meaning of life; “To Preserve and Protect”: the contrastive values of human versus artificial life; “What is a Terminator?”: The Ontology of Fictional Objects; “I Have Data Which Could be Interpreted as Pain”: machines, consciousness, and simulated perception; The T-1000: adaptable machines and emergence; How Did They Build Skynet?: “truthmakers” and knowledge with no source; Andy and the Turk: killing the innocent to save the innocent or Are scientists responsible for their inventions?; “Terminatrix”: the T3 gynoid , feminism, and trangressive cyborgs; “Should we Stop the Future?”: Conservatism and the “Terminator Argument” in bioethics; “The Closest Thing to a Father I Have”: John Connor & the Terminator; “Desire is Irrelevant, I am a MACHINE”: Who is Responsible for the Terminator’s Actions? Or freewill vs determinism; “Assume the Shape of Anything it Touches”: The Metaphysics of Transformation in T2 & T3; The Govinator: Fantasy and reality in politics; Does the Future Exist now?: The nature of spacetime and reality; Embodied Artificial Intelligence: Is AI actually possible, and if so, how close are we to creating it?; Monstrous Technology: From Frankenstein to the Terminator.

Submission Guidelines:

1. Submission deadline for abstracts (100-500 words) and CV(s): September 8, 2008.

2. Submission deadline for drafts of accepted papers: November 3, 2008.

Kindly submit by e-mail (with or without Word attachment) to: Richard Brown at

Aristotle on Universal Quantification

I was rereading the Posterior Analytics in preparation for my lecture today and I was struck by the following passage from Book I chapter 4 (72b 28-30)

Now I say that something holds of every case if it does not hold in some cases and not others, nor at some times and not others; e.g. if animal holds of every man, then if it is true to call this a man, it is true to call him an animal too; and if he is now the one, he is the other too;

Here Aristotle seems to be defining ‘all A’s are B’s’ in terms of a universally quantified conditional statement (for any thing (and/)or for any time, if that thing is an A then that thing is a B). This sounds surprisingly modern (indeed, by the end of the chapter he seems to be talking about universal instantiation), since most of us were told in our logic classes that rendering universal statements in terms of a quantified conditional is supposed to correct an error in Aristotle’s logic (i.e. the error of thinking that ‘all’ implies ‘some’). But if we take Aristotle at face value here the way he formally defines ‘all’ will give us perfectly good truth conditions for ‘all A’s are B’s’ even if there aren’t any A’s at all.

So it doesn’t seem that Aristotle’s logic is committed to the existential import of universal affirmative statements (though I know that this isn’t Artistotle’s position since he is clear that No A are B is the contrary of all A are B (i.e. they both can’t be true. He gives as examples ‘all men are just’ and ‘no men are just’)). I wonder if Aristotle had thought explicity about empty categories if he would have rejected the contrary bit from On Interpretation


Thinking about this a bit more it occurs to me that what this shows is the implicit truth-conditional definition of the conditional Aristotle is using. ‘If p then q’ From what he says we can see that the sentence will be true when p is true and q is true and it will be false when p is true and q is false (cf his evidence in Post. A. 72b 30). He does not say anything about the case when p is false, but we can infer a bit about this condition by his claim about contraries. Since when All A’s are B’s is true No A’s are B’s must be false we know that the conditional cannot be counted as true when teh antecedant is false (that would render both of these statements true and so not contraries). So, in the F F and F T combinations the conditional must be counted as false. That satisfies the requirement that the two cannot be true together. So we can see a kind of operator being defined here; let’s call it ‘xxx>’. ‘xxx>’ is defined truth functionally as

P         Q     P xxx> Q

t          t        T

t          f         F

f          f         F

f          t          F

Is the ‘XXX>’ connective a connective from relevance logic? No, it is just the ‘&’ of classic first-order logic…this fits very nicely with the metaphor of universal quantification as a giant conjunction…