Thursday, September 24, 2009

Two ways to make an indispensability argument in ethics

In this post I'll quickly go over the Quine-Putnam indispensability argument in math, and describe two ways that I can think of applying this argument to ethics.

Here's a version of the indispensability argument (and it's sorta sloppy with the ideas, but hopefully clear)

(1) We should believe that something exists if, when we describe the world with our best scientific theories we are forced to speak as if that something exists.
(2) When we describe the world with our best scientific theories we are forced to speak as if mathematical entities exist.

Therefore:
(3) We ought to believe that mathematical entities exist.


Now, how could we apply this argument to ethics? In short, we can change premise (1) above, or we can change premise (2). Here's how.

Version #1:

(1) We should believe that something exists if, when we describe the world with our best scientific theories we are forced to speak as if that something exists.
(2) When we describe the world with our best scientific theories we are forced to speak as if ethical entities exist.

Therefore:
(3) We ought to believe that ethical entities exist.


Would it shock you to learn that such arguments have been made? I'm still at a very low level of familiarity with this kind of argument, but it's my impression that Sturgeon makes an argument very similar to this one. He argues that we should believe that ethics is objective, because if we don't believe that ethical statements are literally true and objective we are at an explanatory loss! I need to read more about this, and I also need to read about the relationship between the indispensability argument and inference to the best explanation.

Here's the second, less audacious version of the argument applied to ethics:

Version #2

(1) We should believe that something exists if, when we do something that we are really committed to taking seriously we are forced to speak as if that something exists.
(2) When we do that something that we are really committed to taking seriously we are forced to speak as if ethical entities exist.

Therefore:
(3) We ought to believe that ethical entities exist.


In short, this version can get off the ground by asking why, in the original Quine-Putnam version of the argument, we let science decide what we're committed to existing? Then you say, "the reason we give science such a privileged position is because X". The next step is to argue that there is something else that is X, and that something else makes us committed to ethical entities.

Just to make something up that sounds the tiniest bit plausible: Why do we say that science has the ability to determine what we're committed to? Because science helps us live our lives in safety. If we weren't to take science seriously then our lives would be unsafe! But that means that anything else that is indispensable for living our lives in safety should have the same status as science, with respect to its ability to determine what we believe in. Perhaps we believe that ethics is necessary for living our lives in safety--otherwise chaos in society would break out!--so we need to take ethics as seriously as science. And then you argue that you can't talk about ethics without believing in ethical entities, so you're justified in believing in ethical entities. This argument isn't sustainable, but it's the form of the argument, the move that's made, that I want to draw out.

As it happens, David Enoch takes an approach that resembles this one. I need to read him more carefully, but he talks aobut non-explanatory indispensabilities.

So we're in good shape! We've recognized, abstractly, two ways that the argument could go, and we've found some names who make such arguments. Plus (and I didn't tell you this yet) I found a couple articles that review both of these strategies. One of them is by Brian Leiter. So we're making some progress here.

"What if we're ALL in the matrix?"

So, one of the stereotypes of philosophy is that it's a field that trades in justifying counter-intuitive things that nobody actually would seriously believe. Like, nobody believes that we live in a matrix or that experience is some dream. Right, yeah, but can you, you know, prove it? Well no, and I don't really care to, is the response that comment probably deserves.

But the truth is that the defense of counter-intuitive claims constitutes a lot of philosophy. I mean, that's predictable in a way. If something's intuitive, there's a good chance that it'll be said pretty early on in the discussion and won't be so interesting. And after a while, if you study a field long enough, you begin to lose your intuitions. This is a feeling familiar to philosophers of language and to linguists--you spend hours trying to explain why an analysis of language is bad because it runs counter to our intuitions about language, and by the time you're done you can't remember which one was the intuitive analysis and which was the non-intuitive one.

My introductory textbook in philosophy of math starts by saying that mathematics stands out because its a priori--that is, you don't bring empirical evidence to support the claims of math. And that's standard, and that's intuitive. After all, has anyone here ever looked outside to see if their math problem was correct? That having been said, Quine makes the claim that math is empirical, and there is no such thing as a priori knowledge at all. So math is not a priori, and you do figure out what math is correct by looking at the world. (As a matter of fact, Quine uses this method to throw out large areas of math as being fictional).

One reason I like philosophy is because I like engaging in the practice of shifting my perspective. I think it's really cool to see a plausible version of something that I used to think was really crazy (like empiricism and mathematics, the claim that mathematics constitutes a posteriori knowledge). Moreover, it's important for figuring out where the stable resting points are in philosophy. If you restrict yourself to what seems intuitive, you'll be missing out on a lot of stable points in philosophy, a lot of viable positions.

So I don't mind when somebody says "Maybe we're all in the matrix" even though it's really counter-intuitive and there's very little chance that I'll believe it. OK, that's not true. I do mind. But not because I don't like dealing with possibilities that run counter to my intuitions. I do, and I think it's fruitful, but the matrix thing has just been overdone already. So, lesson: wild ridiculous claims=good. Talking about the matrix=bad.

Tuesday, September 22, 2009

An indispensability argument for math

I just need to get this on the table, because it's basic to the topics that I'm currently learning more about. I'm going to quickly present the Quine-Putnam argument indispensability argument here, so that I can build off of it and delve deeper in future posts. Just to experiment with form a little bit here, I'm going to make it into a series of dialogues.
----
A: Zebras exist.
B: What makes you say that?
A: Well, I observed a bunch of zebras. I saw them. They're over there [points to zebras].
B: So what? That's inconclusive. You could be hallucinating.
A: That's hardly the best explanation of the fact that I observed those zebras. The best explanation is that I'm not hallucinating, and that there's a bunch of things over there, and those things are called zebras.
B: Fair point. You're always justified in believing things if belief in them is necessary for the best explanation you have of the evidence.
----
A: Electrons exist.
B: What makes you say that?
A: Well, I observed a bunch of stuff [note: I don't know physics], and the best explanation I have of it is that there is something that exists that we hadn't previously known of. I call it an electron.
B: Oh, fair point. After all, it's the best explanation that you have of the evidence, and that explanation requires you to believe that electrons exist.
----
A: Numbers don't exist.
B: Wait a second, that doesn't sound right.
A: Why not?
B: You believe in zebras and electrons because your best explanation of the world requires your belief in their existence, right?
A: Right.
B: And what does it mean for your explanation to "require you to believe in their existence"?
A: I can clarify that. In order to give my best explanation of the world, I have to speak as if zebras and electrons exist. So if I'm committed to my explanation, I can't really avoid being committing to talking as if zebras and electrons exist. I think that this justifies my belief that zebras and electrons exist.
B: Is the law of gravity an important part of your best explanation of the world?
A: Sure--as long as it's up to date with current research...
B: Now, here's the important question for my argument: when you talk about the law of gravitation in your best explanation, is there any way that you can avoid talking as if numbers exist.
A: Well, errrm, no. How else can I talk about distances?
B: That's my point, then. Your best explanation of the world requires you to talk as if numbers exist. But that's the exact same justification you gave for why you believe that zebras and electrons exist. So if you're justified in believing that zebras exist, then you're justified in believing that numbers exist too.
------

Monday, September 21, 2009

Philosophy is a mess

The point of this post is to show how a discussion that would seem to be restricted to the world of ethics quickly becomes entangled with very different parts of philosophy. (And I'll be paraphrasing Harman throughout). And I take the argument to show that a good philosopher can't study only (say) ethics or only (say) math. The nature of philosophy is such that you need to know your way away around a bunch of different areas.

Is ethics objective--is there a matter of fact that is independent of any one of us, with our biases, whether an action is wrong? Or maybe ethics is (at least) subjective? As I've argued before, this question matters largely because we want to know if we can disagree and agree with what other people think about ethics.

A plausible first attempt at answering this question could sound like this: ethics isn't objective, because the way we justify ethics isn't up to the standards of the rest of our objective knowledge. Take, for example, our knowledge that zebras exist. We know that zebras existing is an objective truth because we can observe zebras with our senses (our eyes see 'em at the zoo or in pictures). But ethics--feh! how do you observe an ethical truth? Now, it's true that some people form ethical beliefs after observing (seeing) something. For example, someone can decide that it's wrong to burn cats after observing a cat burning. But that's not a pure observation, like seeing a zebra. Nope. Rather, what you see and observe is a cat burning, but what you decide is that it's bad, after you observe a cat on fire. But you haven't SEEN bad. There was no "badness" that you saw at the cat burning. What would "badness" look like anyway?!

But, as Hanson points out, this idea runs into trouble. Because you're not just making a claim about ethics here; you're also making a claim about the way we observe zebras.

Is it true that when you see a zebra you've made something like a pure observation, that has nothing to do with how you think? Some people (most people, actually) argue that this is not the case. After all, you know what a zebra is before you look into the world and observe one. You have some kind of theory and understanding about the world in order for you to be able to conceptualize what a zebra is, and that has to come before having an observation of it. To realize this, imagine that I ask you whether bliggles exist. I say that they do, because I've observed them directly. You've never observed them directly, but that's because you have no idea what they are. Would it be right to say that you've observed bliggles when you have no idea what they are? (It turns out the bliggles are what I call the combination you get when you duct-tape a parrot to an elephant, a strange object indeed. I'm not just renaming some normal object.)

The point is: in order to make your ethical argument, you also have to make a completely different argument about the way we observe things in general, and how that counts as justification for our empirical beliefs.

And if things weren't complicated enough, we also have this weird thing called "math." Do we observe all mathematical truths the same way we observe empirical truths? Yes? Then with which of our senses? Our eyes? Sure, we can see that 2 stones and 2 more stones make 4 stones, but have you ever seen 2 million stones be added to 2 million stones, and counted to make sure that we have 4 million stones? No, you haven't. So should we doubt that 2 mil+ 2 mil=4 mil? Well, that makes no sense. So maybe we don't observe mathematical truths. Well, maybe we can be sure about things without observational evidence. But then what about ethics? Maybe ethics gets off the hook, and you can be objective without having observational evidence? Or maybe math gets on the hook, and it isn't objective, just like ethics isn't objective.

So now we have three problems entangled: how do we justify our belief in empirical truths, how do we justify our belief in ethical truths, and how do we justify our belief in mathematical truths? Dissolving this tangle isn't really possible; a good philosopher would need answer to all three of these questions.

So maybe philosophy needs to be done as a whole. This is more the way that philosophy was done in the past than the way that it is sometimes done now. And I think the philosophy that tends to get remembered now, the good stuff, doesn't restrict itself to just one domain. After all, if all of philosophy is really tangled up like this, a good idea in one domain is probably going to be a good important idea in the other domains too.

Thursday, September 17, 2009

Ethics and observation

"Ethics and observation" is the title of the first chapter in Harman's (very readable) introduction to ethics. He is trying to explain what makes ethics problematic in a way that science or math is not. Harman is a particularly good person for me to be reading, because he was a student of Quine's. Quine was the author of the "indispensability argument" in mathematics, which is something that I'm focusing research on.

Quine was an empiricist--a position that I can't think of any good way to characterize, so I'll just say that it's the view that the justification of any knowledge has to come from observation. Empiricism makes a lot of good sense. After all, how do I know that I'm justified in believing that my computer is sitting on a table? Isn't it just that I can observe that my computer is on the table! So just generalize from there, and suppose that all knowledge is like my knowledge about where my computer is. But accounting for math was a sore spot for empiricists right from the beginning. Cuz math doesn't seem to be true because of any empirical observation! You don't look at anything to try to prove that 2+5=7, you just figure it out. Empirical observation seems to be worthless when it comes to math. (I'll post a stronger argument for that at some point; Frege made some good ones, and they were directed against J.S. Mill).

So math is difficult for empiricists. If you're an empiricist, you owe us an account of how math fits into your empiricist framework. Take the logical empiricists. They said that all math is logic, and all logic is empty of content (and here they were inspired by Wittgenstein). So since it's devoid of content, you don't have to worry about how we know things about math; it's empty anyway (does that make sense? def not the way I wrote it). But everything else needs empirical justification.

Quine, who was originally an advocate of this view, destroyed it in his landmark paper "Two Dogmas of Empiricism." What he did with math was, actually way cooler and more radical. He argued that math was actually empirical, and so it's just like all other knowledge. But he didn't do this in a kinda stupid way. Rather, he argued that lots of math is absolutely necessary for science; and that therefore we should believe that math is true. That's a one sentence version of the "indispensability argument for the existence of mathematical objects". Another way of putting it is that inference to the best explanation is the way we justify scientific beliefs, and the truths of math are part of the best explanation of the world in a deep, unavoidable way. This is the argument that I'm going to be looking at more closely in the thesis, if all goes according to plan.

The question is, is ethics different from scientific and mathematical knowledge in this regard? At first glance, obviously it's different. Ethics doesn't seem to be tied to our best explanation of the world, it doesn't seem necessary for scientific practice. In this first chapter Harman makes this argument a bit more carefully, and tomorrow I'll present his argument as a first shot way of distinguishing between ethics and math in an empiricist framework.

Well, I'm really tired and this post didn't really go anywhere. But tomorrow I'm going to be looking at Harman's chapter more carefully.

Sunday, September 13, 2009

Thesis Proposal

Debates about realism in ontology and realism in truth-value are central to both metaethics and philosophy of mathematics. In both fields the existence of objects and concepts central to the field’s practice are debated. But more seems to be at stake when it is questioned whether ethical or mathematical statements have truth-value at all. After all, if ethical statements are neither true nor false, then it would seem that I’m unjustified in criticizing someone else’s moral practice. Likewise, if mathematical statements cannot be false, how can I be justified in criticizing someone for embracing the law of non-contradiction, or other seemingly false claims?

So philosophers of math and ethics share similar concerns; the connections between the two subjects run deeper, though. It is plausible to suppose, for example, that the shared concern of these philosophers stems from a shared set problems facing both math and ethics. For example, it has seemed for many that neither math nor ethics is able to bring empirical justification for their claims. This seems to be a challenge to the objectivity of mathematical and ethical discourse. How can a philosopher of math or ethics respond to such a challenge? A defender of realism could suggest that humans have some way of mathematical or ethical intuition that gives them access to the truth, in a way that is analogous to sensual perception. Another choice is to challenge the premise itself, arguing that math and ethics really can be justified empirically. On the other hand, perhaps the lack of empirical justification suggests that our discourse is actually subjective, not objective. Then either math and ethics are false, or they lack truth-value (then the challenge is to explain why our discourse sounds so objective, and projectivist accounts begin to enter the picture).

What is fascinating, yet predictable, is that all of these positions have been staked out in both philosophy of math and in metaethics. Despite this broad similarity in the landscape of both subjects, there are still some arguments that are particular to either math or ethics. Consider, for example, one of J.L. Mackie’s arguments from “The Subjectivity of Values”: the “argument from relativity.” Stated sloppily, this argument states that the best explanation of widespread, deep and irresolvable disagreements in ethics is that ethical statements are subjective rather than objective. This is a powerful challenge in metaethics, but is not often brought in philosophy of mathematics. Likewise, in philosophy of math a powerful argument for realism is the Quine-Putnam indispensability argument, which argues that we are justified in believing in the existence of some mathematical objects (and therefore given a better chance at maintaining truth-value realism in math) due to their indispensability in expressing our best scientific theory. This is an argument that seems peculiar to math and versions of it are less often brought in ethics.

Given the great deal of overlap between the two subjects, arguments that seem peculiar to either math or ethics provide an important opportunity to explore the relationship between math and ethics. First, is it possible to map one argument into the other’s field? For example, can a plausible version of Mackie’s argument from relativity be made with regards to math? Can some kind indispensability argument be made in ethics? If the answer is “yes,” then we have made some progress to showing some stronger connection between math and ethics. If the answer is “no” then we also have an important opportunity: to investigate closely to determine why the argument failed to be plausible when translated into the other subject. For example, if study shows that the argument from relativity fails to be plausible in math, we should be able to isolate why the argument failed. Whatever the reason for this failure is, it should be a very important difference between the two subjects. In other words, failure for the argument to map between the subjects should isolate an important difference between math and ethics.

My initial investigations have shown me that there are some philosophers engaged in this sort of project. For example, there is a dissertation in NYU being written on ethics and mathematics by Justin Clarke-Doane (Hartry Field, Thomas Nagel, Derek Parfit and Stephen Schiffer are on his committee). Clarke-Doane has argued that Mackie’s argument from relativity applies just as strongly to mathematics than it does to ethics. Another NYU-educated philosopher, David Enoch, wrote his dissertation defending a version of the indispensability argument for metaethics (again, Field, Nagel and Parfit were on the committee).

I propose to write a thesis that continues this line of thought. In order to focus the project, I will pick one argument for or against realism in truth-value that is made either solely in philosophy of math or metaethics. Then I will, following the procedure that I laid out above, see how plausibly the argument translates into the other subject. After I determine how plausible translation is I will be able to make (only modestly, given the scope of the project) some observations concerning the similarities and differences between math and ethics that make translation either plausible or implausible. My continued research on this topic will determine which argument I choose to focus on—my research so far has looked at Mackie’s argument from relativity and the Quine-Putnam indispensability thesis (my interest in these arguments led to the discovery that Clarke-Doane and Enoch had also done work on them, not the other way around), but as I continue this project better candidates for arguments to focus on will emerge (analyzing the argument from queerness or the attempt to identify mathematical with logical truths might yield interesting insights).


Preliminary Bibliography:

Introductory textbooks:

“Thinking about Mathematics” by Stewart Shapiro
“An Introduction to Contemporary Metaethics” by Andrew Miller

Collections:

“Philosophy of Mathematics: Selected readings” edited by Paul Benacerraf and Hilary Putnam
“Essays on Moral Realism” edited by Geoffrey Sayre-McCord

Articles and books:

“Philosophy of Logic” by Hilary Putnam
“Realsim, Mathematics and Modality” by Hartry Field
“Mathematics in Philosophy” by Charles Parsons

“Essays in Quasi-Realism” by Simon Blackburn
“Moral Realism and the Argument from Disagreement” by D. Loeb
“How is Moral Disagreement a problem for realism” by David Enoch
“Moral Realism and the Foundation of Ethics” by David O. Brink

Thursday, September 10, 2009

List of things to read

Justin Clarke-Doane: Disagreement in Mathematics
David Enoch: An Argument for Robust Metanormative Realism (at least part of it)
Soloman Feferman: The development of programs for the foundations of math
Peter Koellner: Truth in math: the question of pluralism

Need to find: paper on Mackie's argument from disagreement, and need to think more carefully about Mackie's argument from queerness and how that would apply to mathematical objects. Need to think more about the indispensability argument.

Here's one way that the proposal could look:

Introduction: similarities between the challenges to realism in math and ethics, and the similarity of approaches in defending realism, this thesis aims to show the fruitfulness of thinking this through more systematically by looking at arguments in math and ethics that haven't been applied to the other, thinking about whether they can be applied and what the major differences moving things around is.
Chapter 1: Argument from disagreement and queerness in Math
Chapter 2: Indispensability argument in ethics
Chapter 3: What are the significant differences between math and ethics that are exposed from this analysis?