My position on evidence is I think fairly similar to the position Clayton Littlejohn takes when he says “evidence is non-inferential knowledge”:http://claytonlittlejohn.blogspot.com/2009/11/scattered-thoughts-fantl-and-mcgrath-on.html. I think, as I say in “this old paper”:http://brian.weatherson.org/EK.pdf, that evidence is basically knowledge that is the output of a Fodorian module. The differences between our positions aren’t great. But I think there are some differences. This kind of case brings out some of these differences.

bq. Graham, Crispin and Ringo have an audience with the Delphic Oracle, and they are told ¬ p ∨ q and ¬ ¬ p. Graham is a relevant logician, so if he inferred p ∧ q from these pronouncements, his belief in the invalidity of disjunctive syllogism would be a doxastic defeater, and the inference would not constitute knowledge. Crispin is an intuitionist logician, so if he inferred p ∧ q from these pronouncements his belief in the invalidity of double negation elimination would be a doxastic defeater, and the inference would not constitute knowledge. Ringo has no deep views on the nature of logic, but has accepted the classical theory he learned in an undergrad intro class because he doesn’t know there’s any dispute about it. Moreover, in the world of the story classical logic is correct. So if Ringo were to infer p ∧ q from these pronouncements, his belief would constitute knowledge. Now Graham’s and Crispin’s false beliefs about entailment are not p ∧ q-relevant evidence, and Ringo doesn’t have more evidence about logic than Graham or Crispin. So all three of them have the same p ∧ q-relevant evidence, but only Ringo is in a position to know p ∧ q.

This case is meant to do two things. First, it is an argument against a kind of evidentialism about knowledge. It isn’t true that what you know, or even what you’re in a position to know, supervenes on the evidence you have. Graham, Crispin and Ringo have the same evidence, but only Ringo is in a position to know that p ∧ q. That’s because Graham and Crispin’s false beliefs about entailment are defeaters in this context. In general, knowledge doesn’t supervene on evidence because defeaters don’t supervene on evidence.

The other thing it is supposed to do is draw out the idea that there is something problematic about treating logical knowledge as evidence. Ringo knows that ¬ p ∨ q and ¬ ¬ p entail that p ∧ q. Graham and Crispin don’t know this. But this isn’t an extra piece of evidence that Ringo has. Indeed, it isn’t an extra piece of evidence Ringo has for two reasons.

First, Graham and Crispin have all the evidence that Ringo has. They know that logic professors in intro classes say that ¬ p ∨ q and ¬ ¬ p entail that p ∧ q. They just don’t believe that these professors are right. This doesn’t seem like the kind of thing that destroys evidence.

Second, there are reasons tracing back to Lewis Carroll’s “Achilles and the Tortoise” for distinguishing between logical rules and logical axioms. Similar reasons suggest that we should distinguish between between empirical evidence and inferential rules that licence inferences from that evidence. That’s especially true when the inferential rules just are logical rules. So I don’t think that what licences Ringo’s inference of p ∧ q is an extra bit of evidence, it’s rather a rule of logic.

But Ringo knows that rule is correct. Indeed, it might even be a non-inferential piece of knowledge for him. (If need be, make Ringo smart enough in the example that he can simply see that certain inferences are valid.) Basic inferential rules aren’t things we know inferentially, they are things we use to get inferential knowledge. So if evidence is non-inferential knowledge, they are evidence. But I suspect they are not evidence for the reasons I’ve given here. So I think there’s a downside to the equation of evidence with non-inferential knowledge.

Thanks to the feedback I’ve gotten already on evidence. Here are three other questions that I’ve already got from looking at those suggestions, and thinking about related stuff.

1) In the literature on testimony, there are several writers who deny that testimony is a source of evidence. Rather, they say, testimony provides a kind of non-evidential warrant.

Now I’m rather sceptical that this is the right approach to testimony. But one thing that’s worth thinking about from a perspective of a theory of evidence is what it could mean for this to be true. On some theories of evidence (on E=K for instance) it’s hard to see how this could even be a coherent position. I suspect it is a coherent position, and that’s a reason to doubt E=K. But turning this into an argument requires saying more about what non-evidential warrant might be, and hopefully saying that will provide some clues as to what evidential warrant might be!

It might be helpful here to think about the kind of warrant we get from doing simple logical inferences. When we validly infer q from p, and thereby come to know q, presumably p is part of our evidence. But I don’t think it is true in general that the fact that p implies q is part of our evidence. If it is, then we should also say that the fact that p, and p implies q, together imply q is part of the evidence, and so on ad infinitum, and that strikes me as absurd. So in inference there are things that we know, and that provide warrant, but which are not part of our evidence, properly construed. So I am sympathetic to the idea of non-evidential warrant, though I’d like to know a lot more about how it is supposed to work.

2) It’s interesting to think about what evidence a person has. And it’s interesting to think about what evidence a person has for different claims H, where H is a claim that the person could be considering. Here’s a third question: Which of those two concepts is primary? I sometimes think E=K is best considered as a view where the concept of evidence for is primary, and evidence simpliciter is a derived notion.

What I mean by this is to say that E is part of S’s evidence just is to say that E is part of S’s evidence for some hypothesis, and the order of explanation/analysis here goes from right-to-left. One question is whether that’s the right way to take E=K. (I think it makes the best sense of some arguments for E=K.) The other question is whether it is the right way to think about the question more broadly. Should we analyse ‘evidence for’ by first offering a theory of evidence, and then asking what of that evidence is evidence for the hypothesis in question, or should we analyse evidence by first offering a theory of evidence for different hypotheses, and then asking what propositions are evidence for some propositions or other? This seems like a fairly deep question, and I don’t know how to attack it.

3) In law, evidence typically does *not* consist of propositions. In philosophy we’ve focussed our attention on propopsitional evidence. Or at least we have recently. When Quine said evidence was sensory irritations, he presumably was not saying that our evidence consists of facts about sensory irritations. We might have made a deep mistake here; maybe propositional evidence is just a special kind of evidence.

I plan to think more about the nature of evidence and its role in epistemology. But I don’t know enough about where to start looking in the literature. Really, I only know three kinds of things.

First, there is formal work from Bayesian epistemology, and especially confirmation theory. But I’ve always found that work quite disappointing in terms of its foundations. The issue of just what the E is that goes into Pr(H | E) is never satisfactorily addressed. When you press people informally on it, they seem to fall back on an unexamined version of the phenomenological theory of evidence. This obviously isn’t part of the theory – Williamson has shown how to do Bayesian epistemology with an externalist conception of evidence – but it is what most practitioners seem to assume.

Second, there is work around the debates about evidentialism as promoted by Conee and Feldman. This is all very interesting, though the focus there was more on what evidence does than what evidence is.

Third, there are the debates started by Williamson’s defence of E=K, including in the recent volume of papers on Williamson. This has led to lots of interesting discussions, such as Clayton Littlejohn’s idea that evidence is “non-inferential knowledge”:http://claytonlittlejohn.blogspot.com/2009/11/scattered-thoughts-fantl-and-mcgrath-on.html. I have a couple of contributions to this, an unpublished paper arguing that “inductive knowledge isn’t evidence”:http://brian.weatherson.org/EK.pdf, and a small aside in “Deontology and Descartes’ Demon”:http://brian.weatherson.org/DDD.pdf suggesting that, for creatures like us, evidence is knowledge gained directly from a perceptual module. This seems to be an interesting, if young, field.

But there must be other stuff out there. What should I be reading?

I’ve been rereading John Bigelow and Robert Pargetter’s “Science and Necessity”, which is full of good stuff. (Sadly, it isn’t in the Rutgers library, so it was a bit harder to read than it should have been.) They open with a defence of the correspondence theory of truth against various rivals. Much like I think the JTB theory of knowledge, and the “UnGettierized” JTB theory (as discussed “here”:http://twitter.com/AidanMcGlynn/status/5994795696) fail because of the paradoxes, I think the correspondence theory of truth fails for the same reason. I assume this isn’t a new point. (It is at least implicit in several arguments Roy Sorensen has made, for instance.) The problem is that (Co) is obviously true.

(Co) (Co) does not correspond to reality.

Assume (Co) corresponds to reality. Then it is true, assuming at least the correspondence theory. So it does not correspond to reality, assuming only the weaker version of the T-schema (that if p is true, then p). That contradicts our original assumption. So (Co) does not correspond to reality. And that’s what it says, so presumably it is true. (Though this step does require a p, therefore p is true inference, which some might find problematic.) So something that does not correspond to reality is true, contradicting the correspondence theory.

Bigelow and Pargetter, like many defenders of correspondence, focus primarily on various kinds of ‘anti-realist’ alternatives to the correspondence theory, such as coherentist and pragmatist theories. But I don’t think those are the major problems for the correspondence theory, or truthmaker like alternatives to correspondence. Rather, the paradoxes are the real problem.

In philosophy of economics through roughly the 1990s, there was a somewhat annoying dialectic that went as follows.

First, a philosopher would come along saying that economists typically make all sorts of implausible assumptions. These include:

• Perfect rationality;
• Perfect information;
• Markets in everything;
• Zero transaction costs; etc.

Obviously these are implausible, and the philosopher will say loudly how absurd it is that we take seriously a discipline built on crazy foundations.

Second, an economist will come along and say that this is all a misreading of the discipline and a sign of ignorance of the state of contemporary economics. It’s true, they’ll say, that every one of those assumptions is made in intro textbooks. But they aren’t made by real working economists. Look, here’s a paper where perfect rationality is dropped, and here’s one where perfect information is dropped, and here’s one where we assume limited markets, and here’s one where we assume zero transaction costs. (If you want real-life examples of my storybook version of history, see some of the responses to Daniel Hausman’s “The Inexact and Separate Science of Economics”.)

And at this point it might look like the economist has won. At least I haven’t see a lot of pushback from philosophers from philosophers. But I think the response rests on a scope ambiguity. It’s true that cutting edge work doesn’t make all of the assumptions listed above. Indeed, it’s true that every one of those assumptions has been questioned in some cutting edge work or other. But what’s not true is that there is a large body of mainstream top level work that questions all of the assumptions simultaneously. The steady state of the discipline seemed to be that we’d start with the absurd idealisation, and then relax assumptions very slowly, seeing how far we could go before the mathematics became intractable. (Or, worse still, we had to pay attention to institutional/sociological matters.)

None of this will be news to people who have been following Crooked Timber, because it’s been a major theme of John Quiggin’s posts on the failures of modern economics. (See, for instance, “here”:http://crookedtimber.org/2009/10/13/what-went-wrong-with-new-keynesian-macro-more-bookblogging/, “here”:http://crookedtimber.org/2009/10/12/bookblogging-micro-based-macro-2/ and “here”:http://crookedtimber.org/2009/11/19/bookblogging-what-next-for-macroeconomics/.) But it was sort of news to me. If I’d realised this point about scope ambiguities 10 years ago, I might have written several papers in philosophy of economics in the meantime. It’s obviously a bit late for that. But I do strongly recommend these Quiggin posts, which are both relevant to live policy debates, and connect to several philosophically fascinating questions about scientific methodology and the nature of rationality.

This post on Curbed about “scaffolding in New York”:http://curbed.com/archives/2009/11/19/scaffolding_doesnt_save_it_kills.php resonated a lot with my feelings about one aspect of New York. Before I moved here, my mental picture of a typical New York street had scaffolding over it. My mental picture of midtown (where I don’t spend a lot of time) still has that scaffolding over the streets, especially 7th avenue and Broadway. A lot of it must be unnecessary. I haven’t been to Hong Kong in 20 years, so I can’t make any comparison there, but as they say, there’s nowhere near this much scaffolding in London or Paris.

I sometimes read people saying that they don’t like the ‘boxed in’ feel of Manhattan. On the whole, I don’t really get that – what Manhattan loses in a little light from the tall buildings it makes up for by having such a high portion of public spaces. And unlike most parts of America, you can use those public spaces without wearing 2 tons of metal armour. But in those neighbourhoods where you’re always walking under a nine foot high quickly constructed wood ceiling, I can see the downside. The solution is just less scaffolding!

There have been several interesting reviews at Notre Dame Philosophical Reviews recently. These include some of the first reviews to come in since I joined the editorial board there. So far that’s involved suggesting potential reviewers and reading reviews that come in to check them over before publication. Don’t be surprised if you see a slight uptick in the proportion of Scotland-based reviews in the next few months!

But the three reviews I wanted to highlight weren’t ones I had anything to do with. They are

• Debra Satz, Rob Reich (eds.), “The Political Philosophy of Susan Moller Okin”:http://ndpr.nd.edu/review.cfm?id=18245, Reviewed by Ann E. Cudd, University of Kansas
• Richard Holton, “Willing, Wanting, Waiting”:http://ndpr.nd.edu/review.cfm?id=18225, Reviewed by Carl Ginet, Cornell University
• Galen Strawson, “Selves: An Essay in Revisionary Metaphysics”:http://ndpr.nd.edu/review.cfm?id=18205, Reviewed by Sydney Shoemaker, Cornell University

I hadn’t actually realised that Richard Holton had written up his work on will and intention into a book, and it’s something I’m looking forward to reading. I’ve learned a lot from Richard’s papers on these topics over the years. (Obviously much of “Deontology and Descartes’ Demon”:http://brian.weatherson.org/DDD.pdf draws on ideas that he developed, for instance.) And although it looks from the review that the book recapitulates a lot of what’s in the papers, seeing the ideas as a unified whole will I’m sure be valuable.

We’ve been publishing a lot of Philosophy Compass articles recently. Here is a selection of what’s just come out.

• Theories of Community in Habermas, Nancy and Agamben: A Critical Evaluation, Brian Elliott
• Günter Figal’s Hermeneutics, Theodore George
• Introduction to the Epistemology of Causation, Frederick Eberhardt
• Moral Contractualism, Nicholas Southwood
• Are Human Rights Essentially Triggers for Intervention?, John Tasioulas
• Carnap’s Logical Structure of the World, Christopher Pincock
• Leibniz on Compossibility, James Messina, Donald Rutherford
• Legal and Moral Responsibility, Antony Duff
• Citizenship and The State, M. Victoria Costa
• Possible Worlds I: Modal Realism, Louis deRosset
• Possible Worlds II: Non-reductive Theories of Possible Worlds, Louis deRosset
• Reviving Whorf: The Return of Linguistic Relativity, Maria Francisca Reines, Jesse Prinz
• Morality and Religion, Tim Mawson
• Teaching & Learning Guide for: Musical Works: Ontology and Meta-Ontology, Julian Dodd

CALL FOR PAPERS

3rd Formal Epistemology Festival: Learning From Experience & Defeasible Reasoning
University of Toronto, May 11-13, 2010

This is the third of three small, thematically focused events in formal epistemology, organized by Franz Huber (Konstanz), Eric Swanson (Michigan), and Jonathan Weisberg (Toronto). This year’s festivities coincide with the 30th anniversary of Ray Reiter’s “A Logic for Default Reasoning” and the 15th anniversary of John Pollock’s Cognitive Carpentry. The event is dedicated to the memory of John Pollock. Confirmed participants include Thony Gillies, John Horty, Mohan Matthen, Jim Pryor, Susanna Siegel, and Scott Sturgeon.

We welcome submissions of papers on topics related to learning from experience, defeasible reasoning, or both. Please send a pdf prepared for blind reviewing to FEF3@utoronto.ca.

The conference website is http://www.utm.utoronto.ca/~weisber3/3FEF/. Some funding for travel expenses may become available.

Deadline for submissions: February 28, 2010.
Notification of acceptances: March 21, 2010.

As part of the setting up of the Northern Institute of Philosophy at Aberdeen, plans are afoot for a new journal for short papers. Here’s a brief description of what the journal will be like.

bq. The Northern Institute of Philosophy (NIP) intends to establish a journal dedicated to the publication of concise, succinct (of less than 4500 words), original, philosophical papers in the following areas: Logic, Philosophical Logic, Philosophy of Mathematics, Philosophy of Language, Metaphysics, Epistemology (including formal epistemology and confirmation theory), Philosophy of Science and Philosophy of Mind. All published papers will be analytic in style. We intend that readers of this journal will be exposed to the most central and significant issues and debates in contemporary philosophy that fall under its remit. We will publish only papers that exemplify the highest standard of clarity.

bq. The philosophical community has been vocal about the need for such a journal (broadly, a second Analysis-style journal) for many years, and the Northern Institute of Philosophy is in an optimal position to deliver one, since the editorial process will be able draw on the wide-ranging expertise of the very extensive network of philosophers and research institutions variously affiliated with NIP. We are thus exceptionally well placed to quickly establish a journal that can attain and maintain the highest standards of contemporary analytic philosophy.

I’m very enthusiastic about this proposal, since I think there is a need for more high-quality venues for publishing in M&E broadly construed. Indeed, I’ve signed on to be the epistemology editor for the journal, assuming it comes in to being.

As part of convincing the powers that be that such a journal will be a good idea, the Northern Institute is commissioning a small market survey. You can take the survey at:

• Northern Institute Journal Survey

.

The more people who take this, the better the journal’s prospects will be.