Saturday, December 29, 2007

The coming term

I haven't yet brought myself to writing a substantive post, but I figure I can talk about the coming term. I'm going to be TAing for intro to philosophy of science, which I am looking forward to. In addition to that I will be taking a class on Quine and Carnap with Tom Ricketts. This will be good because it will flesh out my background in Carnap and I will see another perspective on Quine, having taken a seminar on his work with Follesdal. I will also be taking a class on the epistemology of perception with McDowell. This could be cool. I don't have a lot to say about this. Perception is all the rage around Pitt this year it seems. Finally, I'm going to do an independent study on algebraic logic using Dunn's algebraic logic book. I am really excited about this. It will, hopefully, help motivate me to write some more posts about logic and get those model theory posts off the backburner. I'm hoping to link this to some things about substructural logic and proof theory, since Restall's proof theory book makes the connection between the two. Somehow this term I've gotten interested in relevance logic, and this will, maybe, connect up to this directed study. In addition to this, I need to start doing work for the grant that I got to study Wandering Significance. Thinking and blogging are mutually reinforcing, so I will probably write some posts on it.

Once I finish up a short paper on Aristotle's logic, I can declare victory over this semester. The first term teaching was rewarding but somewhat rough. Teaching three discussion sections a week takes much more time than I expected. It certainly ate into my time doing my own work. A few ideas I had didn't receive the sort of time I had hoped to put into them.
At the start of the term all the new TAs had to go to several seminars on various aspects of teaching. One thing that we didn't have that, in retrospect, would have been nice to have was a seminar on how to teach and do your own work. I will finish this post with a suggestion I got from someone on how to teach and do your own work: shirk responsibility. Wise words.

Monday, December 24, 2007

Nothing of substance

It turns out that between Aristotle and holiday lethargy I did not get much else done. I probably will continue this trajectory until school starts back up again on the seventh of January. I stumbled across this old quote from an interview with William Gibson, a science fiction author I like a lot, that I think is quite nice, so I thought I would share:
"But it's still the same thing -- I make black marks on a white surface and someone else in another location looks at them and interprets them and sees a spaceship or whatever. It's magic."
Magical but not supernatural. In any case, posting will probably be somewhat light for the next two weeks or so.

Tuesday, December 18, 2007

Other people are interested in Brandom

There is a nice little series of posts on Brandom and Habermas and Brandom on objectivity with further comments. It looks pretty good. I'm hoping to get some comments in soon. I have been bogged down in an Aristotle paper which finally started to warp itself up. Once I get done with this I am going to try to write up some more posts, including some much delayed thoughts on model theory.

Monday, December 17, 2007

Evans link

There has been a buzz about Gareth Evans around here recently. I just found this overview of Evans's Varieties of Reference by Rick Grush at UCSD. It could be useful for those brave souls venturing into the work solo or those of us that might venture into it in the near future. [Edit: The picture of Evans on that page, in fact the only picture I've ever seen of him, is amazing. Oh, to have been a philosopher in the 70's...]

Goldfarb on showing

A couple of weeks ago Warren Goldfarb gave a short talk to our TLP reading group on the notion of showing. Explaining the saying/showing distinction is very important to resolute readers of the Tractatus and it is one of the big ways in which the resolute reading is set apart from the others. The traditional reading takes the talk about showing to indicate that there is some inexpressible reality or truth that statements can gesture towards but not outright say. While these things are nonsense, they are informative nonsense in that they help us see the deep truths. The resolute reading wants to do away with that and say that nonsense is just nonsense. Alright, but what do we make of various places in TLP where Wittgenstein says things like what can be shown cannot be said?
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Goldfarb's idea was to look at all the instances of "show" and its cognates (zeigen in German) in the Tractatus and see if they lend themselves to a metaphysically loaded interpretation. There are around 20 instances in the book and a few relevant passages from the Notebooks. He isolated three versions of showing. One is the sense of showing in which a name shows that it is a name and not a relation and a relation symbol shows that it is a relation. One can't say that something is a name, but that it is a name is apparent from what sort of variable it can be substituted for. This is an idea that Wittgenstein most likely picked up from Frege. The other two senses seem to be original to Wittgenstein in the Tractatus. (I can't find my notes on the talk so this bit might be fixed up later.) The second sense is the way in which a proposition shows that it is logically complex. It can be seen in the proposition that a proposition is logically complex or atomic, but not said according to the Tractatus. The third sense is the way in which propositions show what follow from them, i.e. by combining into tautologies. That p and p->q implies q is shown by (p. p->q)->q being a tautology. I got these two senses confused since they are similar. The important difference is between complexity and consequence. The second step is the former and the third is the latter. All three senses are in play in the finished Tractatus. Going through the text, Goldfarb made a pretty compelling case that all instances of showing in the Tractatus involve only showing logical and categorial features of the propositions involved, which would not necessitate any move to more metaphysically loaded readings. Part of the desire to give a more metaphysical reading depends on the discussion of the mystical, which I will get to below. Goldfarb's talk made it slightly hard to see why people were tempted by the more metaphysical understanding of showing at all. I think that the more metaphysical reading is fairly easy to get on the first read or two. However, examining the specific passages with his distinctions in mind did make it difficult to see the need for a more metaphysical reading of those passages.

There were two further points that were important to his presentation. One was what to make of the 'cardinal problem' letter to Russell. Wittgenstein wrote a letter to Russell in which he told Russell that he had not gotten the message of the Tractatus and he said that the cardinal problem of philosophy was the distinction between what can be said and what can be shown. Goldfarb's take on this was that it was directed mostly at Russell and his philosophy of logic. This was probably the least satisfying part of the presentation since he ended up saying that Wittgenstein was emphasizing the point just for Russell. The idea being that the distinction wasn't the cardinal problem but rather a cardinal problem. I'd like to go back over Goldfarb's take on this in comparison to Kremer's recent paper on the topic, but I'm not sure when that will happen.

The other was what to make of phrase that is translated as "shows itself" in Ogden's translation and as "makes itself manifest" in the Pears-McGuinness translation. The German that these come from is "sich zeigen". They are used in connection with Wittgenstein's discussion of the mystical. Goldfarb's suggestion here is that all instances of "sich zeigen" should be seen as expressing something completely different from what is expressed by "zeigen". This would let the resolute readers try to make sense of the discussion of the mystical apart from the rest of the discussion of showing. I hadn't drawn the connection between the two enough to worry about their relation. It seems like a reasonable enough thing to do. All in all it was a great talk and a delightful way to end the reading group for the term.

Saturday, December 15, 2007

On Brandom's so-called inferentialism

Before getting to the post proper, it will help to lay out a distinction drawn, I believe, by Sellars. The distinction is between three sorts of transitions one could make in relation to propositions, for example if one is playing a language game of some sort. They are language-entry moves, language-language moves, and language-exit moves. The first is made through perception and conceptualization. Perceiving the crumb cake entitles me to say that there is crumb cake there. The second is paradigmatic inferential or consequential relations among propositions. Inferring from p&q to p is a language-language move. The third is moving from a practical commitment or explicit desire to action. Borrowing Perry's example, it is the move from thinking that I have to be at the meeting and that the meeting is starting now to me getting up and rushing off to the meeting.

In Making It Explicit, Brandom distinguishes three things that could be meant by inferentialism. These are the necessity of inferential relations, the sufficiency of inferential relations, and hyperinferentialism. The first is the claim that inferential articulation is necessary for meaning. Representation might also be necessary, but at the least inference is necessary. The second is the claim that inferential articulation is sufficient for meaning. In both of these, inference is taken broadly so as not to collapse into hyperinferentialism, which is the thesis that inference narrowly construed is sufficient for meaning. The narrow construal is that inferences are language-language moves. What does this make the broad construal? According to Brandom, it includes the language-entry and -exit moves. In MIE, Brandom defends, I believe, the necessity of inferential relations, although he says some things that sound like he likes the idea of the sufficiency claim. He doesn't think that hyperinferentialism will work. This is because he thinks that for some words, the content of the word depends on causal/perceptual connections. I think that color terms are examples. Additionally, the content of some words exhibits itself in what practical consequences it has in our action and this exhibition is an essential part of the meaning of the word. My beliefs about crumb cake will influence how I act around crumb cake. Hyperinferentialism cannot account for these because the language-entry and -exit moves essential to their meaning are not things hyperinferentialism has access to.

Brandom's claim then, once things have been unpacked a bit, amounts to saying that the narrowly inferential connections, perceptual input, and practical output are necessary for meaning. This seems to undercut the charge that inferentialism loses the world in a froth of words, which charge is mentioned at the end of ch. 4 of MIE, I think. It is also a somewhat looser version of inferentialism since things that are not traditionally inferential get counted as inferential. The inferentialist could probably make a case that that the language-language moves are particularly important to meaning, but I think Brandom's inferentialism stretches the bounds of inference a bit. I'm not sure an inferentialist of the Prawitz-Dummett sort would be entirely comfortable with the Brandomian version of it. By the end of MIE, Brandom's broad notion of inference encompasses a lot. Granted, it is fairly plausible that much of that is important to or essential for meaning. However, I wonder if it doesn't move a bit away from the motivating idea of inferentialism, namely that inference is what is central.

Wednesday, December 12, 2007

A quirk of philosophical speech

I've noticed a speech pattern that sees a lot of action around here. I don't remember hearing it before coming to Pittsburgh, but I wouldn't trust my memory too much on that matter. The pattern is: well, you might think X. The "well" is optional. It is often used as a way of introducing a view or objection. For example: well, you might think that representation is essential for linguistic meaning. Or, you might think that the conceptual is unbounded, which would lead you to object to bare presences like sense-data contributing any sort of justificatory element. Is this a widespread pattern? I don't think this has crept into my speech or writing.

I'm now done grading finals for the class I'm TAing, so hopefully I can get back to putting up contentful posts, like that one on Goldfarb on showing I promised recently.

Monday, December 10, 2007

Problems for constructive empiricism

This is a short thing I wrote up for my philosophy of science class on Arthur Fine's criticisms of van Fraassen's position. I liked it, so I thought I'd share. Apparently in that seminar I didn't make it pass the Scientific Image. The problem wasn't solved, but I think I figured out what the problem is. Solving it will probably require figuring out why van Fraassen adopts the epistemological views he does. No mean task, that.

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In his "Unnatural Attitudes," Arthur Fine finds fault with anti-realism in the philosophy of science in its attribution of an aim to science, which, in the case of constructive empiricism, is that science aims at empirical adequacy.
Upon further examination, this objection breaks into two further, related criticisms, one that says constructive empiricism artificially splits the inferential practice of scientists and one that says the constructive empiricist policy about accepting unobservables is unjustified. I will argue that van Fraassen can adequately respond to the latter. The former turns on broader philosophical disputes between van Fraassen and Fine that cannot be resolved here, but I will attempt to give a response that does not rely on these. In the end Fine's criticisms cast some doubt on van Fraassen's view but they are not decisive against it.

Fine initially criticizes anti-realism for the attribution of an aim to science because an aim distorts our understanding of science. The distortion comes from a desire to "interpret science in accordance with a set of prior, extra-scientific commitments." The extra-scientific commitment of constructive empiricism, namely to empiricist epistemological principles, is built into the demand of empirical adequacy, which van Fraassen says is the aim of science. Empirical adequacy comes bundled with a distinction between the observable and the unobservable.

Despite rhetoric to the contrary, the source of Fine's problem does not seem to be that van Fraassen attributes an aim to science, but rather what the aim is. If van Fraassen did not claim that science aims to provide empirically adequate theories, then part of the motivation for the empiricist epistemology is removed. It need not drop out completely, though, as the epistemology is a consequence of, not equivalent to, the aim. Fine's criticism does not essentially involve an aim being attributed to science. Rather, the heart of the criticism lies with the extra-scientific commitments of the empiricist epistemology.

According to Fine, constructive empiricism's unnecessary need to interpret scientific practice comes from a commitment to empiricist epistemology; Fine says this has two primary principles, that belief requires justification and that only experience can justify belief, both of which are important below. The interpretation holds that scientific evidence builds for belief when the statements in question are about observables and for acceptance when they are not. Fine puts the point by saying that the constructive empiricist "can follow the usual lattice of inferences and reasons that issues in scientific beliefs only until it reaches the border of the observable, at which point the shift is made from belief to acceptance. But the inferential network that winds back and forth across this border is in no way different from that on the observable side alone." There is a uniformity in the scientific inferences about microwaves, on the one hand, and about elephants, on the other. Despite the uniformity, the constructive empiricist divides the commitment and supporting evidence into two categories, one for acceptance and one for belief. The inferences drawn by scientists crisscross the epistemological division between propositions about observables and those about unobservables. Thus, the constructive empiricist imposes an unnatural interpretation on science where no natural boundary exists, which is the first criticism of van Fraassen. While constructive empiricism is, rightly in Fine's eyes, set against "the needless multiplication of entities" it does not follow this policy with respect to "the significance of practices". Even though the inferential practices are uniform, van Fraassen draws a line between some of the involved propositions, dividing them into beliefs and mere acceptances. Before getting to van Fraassen's response to this, it will be helpful to lay out Fine's other objection and respond to it.

Fine's first objection leads naturally to his second which is that constructive empiricism's policy of never going for belief in the unobservable is not justified. Fine doubts that van Fraassen's epistemological considerations successfully underwrite merely accepting, and never believing in, unobservables in all cases. He asks, "Why must it be the case, say for electrons, that the complex history of evidence, successful use, and reasoning at the very best supports belief in the observational reliability of electrons and supports our commitment to behave just as though they exist but nevertheless fails to support the belief that they do exist?" Fine thinks that there is no a priori reason to think that the evidence supporting a theory with unobservables, such as electrons, should never support an inference to the existence of them. Constructive empiricism might be a good heuristic, but the details of the specific cases need to be examined to decide the question of belief. Fine thinks that specific cases will disagree the constructive empiricist stance, although some may agree with it. However this would be a conclusion based on a posteriori knowledge, not a priori commitment.

Against this second criticism, van Fraassen has a reply. Given the principle that only experience can justify belief, van Fraassen's policy about belief is justified, but this would be question begging. Rather, a better reply is to focus on Fine's example of the virtues supporting a theory and how this would support belief in the theory's unobservables. Constructive empiricism says that we are not rationally compelled to believe in unobservables but are rationally compelled to believe in observables. Fine's claim that the theoretical virtues and historical details about theories of electrons support belief in electrons is ambiguous. If he means that the extra virtues provide some motivation for believing, then van Fraassen can agree; they may motivate but not compel. Alternatively, Fine may mean that the extra virtues rationally compel us to believe in electrons, although Fine does not say much about rational compulsion. If the belief in unobservables that Fine recommends is justified, it is justified by something outside of experience. Constructive empiricism, according to Fine, includes the principle that only experience justifies belief. This objection is a consequence of Fine's rejection of that principle.

Even without a defense of the epistemological principle, van Fraassen can respond by denying that anything is gained by believing in unobservables. Believing in electrons does not make the theory more vulnerable to refutation or more empirically contentful. As van Fraassen said, "since the extra opinion is not additionally vulnerable, the risk is - in human terms - illusory, and therefore so [are the gains]." This is not a problem that Fine tackles. He could respond that what is gained by the belief is simplicity of our story about science, but this is not justification for a belief to van Fraassen. The van Fraassen ian point is that what is gained is the claim that there are things that do not and cannot figure in our experience of the world. van Fraassen's response and Fine's rejection of the claim that only experience can justify belief bring this exchange to a standstill. A more promising route is for Fine to point to the first problem, the uniformity of inferential practice, as an example of what is gained by believing, maintaining the uniformity, although this is not justification for a constructive empiricist. This leads us back to Fine's first problem for van Fraassen.

The first problem, the uniformity of inferential practice, seems to be the bigger stumbling block for van Fraassen. The epistemological division does not cut at the joints of the inferential practice of scientists. The challenge is to justify the epistemology. Since settling the issue of whether epistemology of science is needed is beyond the scope of this paper, I will focus on the question of what the relation between the inferential practice and justification by evidence is.

van Fraassen only talks about evidence for a theory as a whole. This evidence will be based on the observable, although it will lend support to the statements about unobservables through supporting the theory. Statements about unobservables serve to simplify connections among observables. The inferential connections are among propositions or statements. Whether these propositions are believed or accepted seems to be a separate issue from what inferential connections they have. The inferential connections are determined, at least for the most part, by the theory which receives evidential support from the statements about the observables. The distinction among the types of commitment to propositions that Fine focuses on does not depend on these connections. The types of commitment and the inferential connections are orthogonal. If they are orthogonal, then it is not surprising that they do not naturally line up. The question now is why this should count against van Fraassen's view.

Fine is oddly silent about what the uniformity among inferences is, even though it is, on this reading, central to his criticism of constructive empiricism. The inferences are not epistemologically uniform, since the evidence for them comes in different forms, depending on their subject matter, although all such evidence will be from observables. Inferences about electrons will be based on different things than inferences about elephants, e.g. the former will may be based on voltmeter readings while the latter may be based on tissue samples. They aren't uniform in their subject matter. Fine's point may be that they are uniform in the scientists' commitment to them, in the form of belief in the premises and conclusions. van Fraassen could agree that they are committed but take issue with the further commitment in the form of belief. van Fraassen does not see it as a problem that most scientists take themselves to believe in all the entities they study, because the question is a philosophical one. No matter the actual views of scientists, all that is needed is the commitment to test the theory's empirical adequacy, and this requires no more than acceptance of unobservables and belief in the observable. van Fraassen's view can then maintain a uniformity among the inferences, commitment to using them to test the empirical adequacy of a theory, even though this is likely not the uniformity that Fine points to.

The heart of Fine's criticism is that the epistemological division is artificially imposed on the inferential practices, which are not themselves problematic. A view that adds something artificial to an otherwise unproblematic phenomenon is not thereby refuted by the artificiality. van Fraassen's reasons for drawing the line where it is relies on a criterion, observability, that while artificial with the respect to the inferential practices is not itself ad hoc. In fact, van Fraassen is able to maintain an important, natural uniformity among the inferences, as outlined above. However, given that van Fraassen thinks that being able to make sense of scientific practice without the inflationary metaphysics of realism is reason in itself to choose constructive empiricism, by parity of reasoning being able to make sense of scientific practice without van Fraassen's extra epistemology is reason to choose Fine's view over constructive empiricism. It looks like Fine's criticism should count against constructive empiricism by van Fraassen's own lights.

In conclusion, Fine's objections push one's intuitions against constructive empiricism but they do not decisively refute it. They cast doubt on the necessity of the epistemological distinctions for our understanding of science, undermining the impulse to enrich our epistemology, but they do not provide us reason to think that the epistemology gets things wrong. van Fraassen is able to respond to Fine's criticisms, but the response to the second objection results in both sides digging in their heels. More completely responding to Fine would require a more detailed defense of the empiricist epistemological principles van Fraassen uses. Without that, the responses give on behalf of van Fraassen get him a draw.

Pitt-CMU conference deadline extension

The deadline for the Pitt-CMU conference was originally today. It is being extended to [Edit: Monday, December 17 (I messed up the date.)]. Please submit if you are interested!

An anecdote

We had the last of the Tractatus reading group meetings on Friday. For our final session, Warren Goldfarb read two short papers on the notion of showing and discussed them with us. I want to write up something about that, but I wanted to mention an anecdote he opened with. He said that he hadn't published much of his stuff on the Tractatus. He then said that at one of his talks he was introduced as, "Warren Goldfarb, whose unpublished work on the Tractatus are de rigueur for any serious student of that work." I found that amusing. Hopefully I will get to the substantive post later tonight or tomorrow.

Monday, December 03, 2007

Van Fraassen on explanation

This is a note I wrote on Salmon and Kitcher's criticisms of van Fraassen's view of explanation in the Scientific Image. It is a little flawed in that the defense I gave in the last third doesn't mesh with what van Fraassen says in the book. I didn't realize this when I wrote it though. Alas. Up until then I think it is not bad though. This is also the thing I tried to post the other day that Blogger kept eating.

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In their article ''Van Fraassen on Explanation,'' Salmon and Kitcher charge van Fraassen with presenting a theory of the pragmatics of explanation that fails to be a pragmatic theory of explanation. This is a hefty charge because van Fraassen denies that there is any sui generis explanatory virtue and defends this claim by providing a theory of explanation that purports to show how explanation is merely pragmatic. In this paper I will present two of Salmon and Kitcher's objections to van Fraassen's theory of explanation. I will then present replies on behalf of van Fraassen and argue that the criticisms do not undermine his project. I will close by presenting what seems correct in Salmon and Kitcher's.

Briefly, van Fraassen sees explanations as answers to questions of the form ''Why is Pk the case?'' A question Q in a given context can be identified with the triple (Pk, X,R), where Pk is the topic of the question, X is the contextually determined contrast class for Pk, and R is the contextually determined relevance relation. An explanation is an answer A to some 'why' question such that the A stands in R to (Pk, X). This makes van Fraassen's theories of explanation and 'why' questions heavily dependent on context. This is explicit at the end of the chapter on explanation in the Scientific Image, where van Fraassen says, ''The discussion of explanation went wrong at the very beginning when explanation was conceived of as a relationship like description: a relation between theory and fact. Really it is a three-term relation, between theory, fact, and context.'' Finally, for evaluating answers we need the background theory K and the part K(Q) that is salient to the question, both contextually dependent. With this background in mind, we will move to the objections to van Fraassen's account.

I will focus on two of Salmon and Kitcher's arguments against van Fraassen which deal with the relevance relations. One is that without any restrictions on what counts as a relevance relation, van Fraassen's account of explanation reduces to triviality. The other is that without any restrictions on relevance relations, van Fraassen's theory of explanation cannot rule out bad explanations without incorporating elements that undermine the claim that explanation is merely pragmatic.

According to Salmon and Kitcher, to reduce van Fraassen's account to triviality, let Pk be a true proposition and X a set of propositions containing Pk and whose other elements are all false. Let R be {( A, ( Pk, X))}U S where S is any set of pairs of the form ( B, ( Y , Z)) where B and Y are propositions and Z is a set of propositions containing Y. Further, S cannot contain any pairs ( B, ( Y , Z)) such that B is true and ( Y , Z)=( Pk, X). Thus, for any true propositions A and Pk, there is a question Q such that A answers Q and Pk is the topic of Q. The conclusion is then: ''If explanations are answers to why-questions, then it follows that, for any pair of true propositions, there is a context in which the first is the (core of the) only explanation of the second.'' Salmon and Kitcher think this is a reductio of van Fraassen's position. They later go on to say that ''if van Fraassen's account does not contain context-independent principles that preclude assigning [trivializing propositions] to K(Q)'' then the above problems will arise. However, a closer examination of their argument will not support the reductio conclusion.

Salmon and Kitcher's argument is not a reductio. Assuming that for each triple of topic, contrast class and relevance relation, there is a context that generates it, then all they have shown is that for each topic and explanation there is a context in which the latter explains the former. What they need for reductio is that for any topic and explanation, the relevance relation for a given context will be the one constructed above. If van Fraassen's account said that any true proposition were an explanation for any question topic in a context, then it would be trivial. However, this is not the case. Some propositions will not explain some question topics in a given context although they could explain the topic in other contexts as the relevance relation of the context would be different. Thus, their reductio fails.

To see why their argument fails, it is helpful to note that the construction above does not invoke context. The contrast class X, the relevance relation R, and the background theory K are all determined by the context, not by the theorist. Formally van Fraassen leaves open the possibility that there are contexts such that for any true proposition they provide contrast classes and relevance relations such that the proposition explains the topic at hand, but this is, prima facie, not different than other theories of formal pragmatics. For example, David Kaplan's theory of indexicals allows contexts in which the speaker is not at the location of the context or at the time or even in the world. These are in a way deviant contexts, but they are formally allowed. Kaplan suggests a natural way of restricting attention to non-deviant contexts. Turning back to van Fraassen's theory, the possibility of unusual contexts is not a reductio of his position. The claim that there is no context in which a certain proposition would explain a given topic is quite strong, and various science fiction examples should provide inductive counterevidence to this claim.

One of Salmon and Kitcher's criticisms of van Fraassen's theory, and a possible reason why they do not mention context in formulating this objection, is that van Fraassen does not indicate any way in which the contrast class or the relevance relation are to be read off of the context. Looking again to Kaplan's theory of indexicals, the formal contexts are quadruples ( cA,cT,cL,cW) of a speaker, a time, a location, and a world. It is fairly straightforward to figure out which formal context corresponds to which concrete context. The speaker cA will be the person talking and cT will be the time that person is talking. There are some complicating details, such as the extent of the location region. Ignoring these for the moment, the formal contexts are comprised of features that are easily read off of a concrete context. Returning to van Fraassen's theory, a difference emerges. The contrast class and relevance relation are less straightforwardly read off the concrete situations. We will return to this point in the conclusion.

The other objection of Salmon and Kitcher to be discussed is that without any formal requirements on relevance relations, van Fraassen's account allows bad explanations and the only way to rectify this makes explanation cease to be merely pragmatic. Their examples follow a pattern, so we will focus on their example of the astrological explanation of the date JFK was assassinated. The setup is that the contrast class is the set of propositions saying that JFK died each day in 1963 together with one saying that he survived 1963. The topic Pk is that he died on 11/22/63. Salmon and Kitcher stipulate that R is the relation of astrological relevance in which the answer stands to the contrast class and the topic. The answer consists of the conjunction of a true description D of the positions of the heavenly bodies, the proposition that if D then Pk, and the denial of everything in the contrast class except Pk. Salmon and Kitcher claim that van Fraassen's theory says this is an explanation. Further, they think that van Fraassen cannot rule out the answer as being astrological because it invokes only facts that are part of the background theory K, i.e. astronomical facts. The only way out of this predicament, according to Salmon and Kitcher, is for van Fraassen to make it so that the relevance relations are not determined solely by merely subjective factors. They say, ''[van Fraassen] ought to be equally serious about showing that relevance is not completely determined by subjective factors. If we are talking about distributions and redistributions of personal probabilities, they must be subject to some kinds of standards or criteria.... To be scientifically acceptable, the redistribution of probabilities must involve differences in objective probabilities...'' However, the move to more objective determinations of relevance and to objective probabilities introduces a non-pragmatic aspect into explanation, undermining van Fraassen's claim that the explanatory virtue is just pragmatic.

Van Fraassen has two responses available, both rejecting excessive assumptions Salmon and Kitcher need for their arguments but to which van Fraassen is not committed. The first of these is that the background theory K includes only contemporary science, possibly with some additional factual information. Thus, in their example given above, the astronomical information is part of K but the astrological beliefs that the agents have and that make it a good explanation to them are not. This provides space for including suspect relations as relevance relations and getting around van Fraassen's admonition that explanation shouldn't rely on old wives' tales. This allows enough space between K and the agents' beliefs to allow Salmon and Kitcher's problems to enter.

Van Fraassen should reject this construal of the background theory. Van Fraassen says, ''[K] is a factor in the context, since it depends on who the questioner and audience are.'' Since it involves who the questioner and audience are, it would seem that van Fraassen means to include in K at least some of the beliefs of the agents in question. There is nothing to debar them from having mistaken or misguided beliefs, e.g. that astrology is true, which are part of K. Since K is not restricted to just contemporary science, van Fraassen has a response to their argument. He should deny that there are no astrological propositions in K. One of the agents involved in the exchange takes the explanation to be good precisely because they have astrological beliefs, so they should figure in K. If van Fraassen is entitled to claim that explanation should not be based on old wives' tales then this will provide a way for him to rule the astrological explanation out as an explanation.

Van Fraassen has another response to Salmon and Kitcher's argument. They assume further that the only solution to the problem is to make the relevance relations more objective and the probabilities involved into objective probabilities. This is a crucial step toward their conclusion that explanatory virtue is not just pragmatic. If the account must involve these objective features then it looks like explanation is not just pragmatic as it latches on to objective features of the world, above and beyond what van Fraassen thinks explanatory virtue involves.

The second response is to deny their crucial premises that the relevance relation and explanation must reflect objective probabilities. Constraints can be put on relevance which do not require tying it and explanation to objective probabilities. Van Fraassen says that ''observable is observable-to-us,'' so it is to be expected that relevance would be relevance-to-us. The relevance relation should depend on K, which van Fraassen would allow to include the beliefs of the agents, as well as current science, to give content to van Fraassen's claim that good explanation should use good science. This ties relevance to subjective factors, in the sense of relying on the subjects involved, possibly including personal probabilities. However, this need not count against it since the subjects and their beliefs are things science investigates, and so, in a sense, objective. Salmon and Kitcher have given no reason to demand more objectivity than that.

Without Salmon and Kitcher's crucial premises concerning relevance, the pressure on van Fraassen's theory to give up the claim that explanatory virtue is just pragmatic disappears. Salmon and Kitcher's argument that van Fraassen's theory requires explanation to have its own non-pragmatic virtue does not work against van Fraassen's position. However, part of their criticism still stands.

At the heart of Salmon and Kitcher's criticism is the charge that van Fraassen does not place any formal constraints on what constitutes a relevance relation while also claiming that not all relations between a proposition and a suitable ordered pair count as genuine relevance relations. This makes the relevance relation an unexplained explainer. It does a lot of the work in van Fraassen's account of explanation, but there are no constraints on it or indications of what counts as a relevance relation.
As was said above, the relevance relations are less straightforwardly picked out of a concrete context than the speaker. Van Fraassen needs to give an account of how the context determines the relevance relation. Without such an account, van Fraassen has just shifted the focus from problems of explanation to problems of relevance.

While Salmon and Kitcher's arguments do not work against van Fraassen in the way they claim, they do highlight demands on the relevance relation. The relevance relation should be tightly connected to the background theory. It should involve the beliefs and intentions of the agents involved in the explanation. Salmon and Kitcher supply a promising suggestion: isolating what look like relevance relations for different sciences at different times and generalizing from there. They have not shown that no account of relevance can be given and the pressure is on van Fraassen to supply such an account. If one cannot be given, then Salmon and Kitcher's arguments will need to be reevaluated.