Monday, February 20, 2012

Week 2: Explanation and Realism

Last week, I asked (among other things), “Why should we care about the relationship between explanation, understanding, and truth?” One answer to this question is that explanatory considerations are frequently used to argue for the objectivity of our discourses Specifically, IBE is used to justify various forms of realism. Broadly construed, realists claim that some philosophically controversial part of our discourse (e.g. about unobservable entities in science, about the external world, other minds, morality) refers to mind-independent truths. Realists who do this via IBE claim that these mind-independence truths best explain the relevant evidence. Hence, realists who deploy IBE claim that there is an intimate relationship between our best explanations and the truth. Indeed, anybody who uses IBE seems committed to this claim. After all, a good inference transmits the truth of its premises to its conclusion. So, endorsing IBE entails accepting that good explanations are a reliable guide to truth. (People might disagree about whether mind-independent truths best explain the relevant evidence, as Harman and Frost-Arnold do in our readings.)
            There are at least three related domains in which IBE is used to justify realism. First, scientific realists argue that claims about the unobservable posits of scientific theories (e.g. subatomic particles) are true because otherwise the success of science would be unexplained. This is called “The No-Miracles Argument,” and it has received its fair share of criticism, e.g. (Frost-Arnold 2010).  Second, we’ll skim Thagard’s (2000)’s chapter, “Reality,” to get a sense of how IBE can justify realism about certain metaphysical issues. Finally, we’ll read Harman’s “Ethics & Explanation,” which denies moral realism on the grounds that it does NOT provide the best explanation of the relevant phenomena. Finally, we’ll read Sturgeon’s “Moral Explanations” for a rebuttal of Harman’s position.
            So, one answer to the “Why care?” question is that you should care about the relationship between explanation and truth because it figures prominently in discussions about the objectivity of various kinds of discourse. To that end, it would be good to know:
(1)  Whether IBE provides a sound justification for this position.
(2)  If IBE can’t provide such a justification, whether it’s more defensible to:
a.     Reject realism (i.e. become an antirealist), or
b.     Find a different justification for realism.


  1. This may end up being a tangential point, but I wanted to note a claim that Thagard makes in his chapter, "Reality." On p. 101, he says, "conceivability is a poor guide to reality, and dualism must be evaluated with respect to its explanatory coherence, not on conceptual grounds tainted by prior beliefs."

    The upshot of the claim seems to be that thought-experiments, a popular weapon of philosophers, are at their core neither evidence for nor against a certain position. Intuitively, I agree with this. The thought-experiments I have encountered always leave me wanting, and I cannot help but feel that IBE provides a slightly better model for examining the world.

    My question, then, is this: Is conceivability a legitimate/useful philosophical tactic?

    Disclaimer: I use conceivability arguments all the time, but I don't think, in the end, that any conceivability argument would ever convince me of a given position.

    1. When I read that bit I ran through all the same stuff I always think about when conceivability arguments come up. I agree with Josh about the slipperiness of thought-experiments as intuition-pumps generally, but in this specific instance I think something a little different is going on. Here’s my take.

      1. Obviously, something being conceivable doesn’t make it the case. But for conceivability arguments to work at all, one has to hold that something being conceivable makes it logically possible, and conversely that if a thing is logically impossible, it is inconceivable (one could take issue with these premises but if somebody’s making a conceivability argument, they probably assume it, so let’s allow it for the sake of argument).

      2. Now, there can be empirical facts that make certain things logically impossible. For example, it is logically impossible that my computer screen . Or, as Kripke likes to point out all the time, it’s logically impossible that Hesperus and Phosphorus (the Morning and Evening Star, which are both Venus), be two different planets. They’re not. (Of course, there’s a possible world where there are two different planets called Hesperus and Phosphorus, but then at least one of them would not be called ‘Hesperus’ or ‘Phosphorus’ in our terminology. As we use the terms, it’s logically impossible that they not be the same, because it’s impossible for a thing not to be itself.)

      3. So a valid argument could run as follows:
      If proposition x is logically impossible, it is inconceivable.
      If empirical fact e is the case, proposition x is logically impossible.
      Empirical fact e is the case.
      ∴ Proposition x is inconceivable.

      Now let’s say proposition x is “my mind is not identical to my body.” Identical here again means numerical identity – exactly the same thing. We say Hesperus and Phosphorus are the same because they happen to be names that picked out the exact same object, and so they have all the same traits – both orbit the Sun at a specific distance, have a specific mass and size and atmosphere and so forth, because they’re the same planet.

      Now check it out. If it is true that I can conceive of my mind being separate from my body, then it means there must not be any empirical fact e which renders that proposition impossible. But if the mind were identical to the brain, this would be just such an empirical fact. Therefore (running the argument above) the mind is not identical to the brain.

      I think people (including Thagard here) often miss the point of conceivability arguments as relates to dualism. It’s not that “I can conceive of the mind apart from the body, therefore perhaps the mind is separate from (i.e. not identical to) the body (or brain).” It’s that, if they were identical, I oughtn’t be able to even conceive of them being separate.

      There are probably objections, but I think this kind of argument deserves a much more fleshed out response than Thagard’s simple “conceivability is a poor guide to reality” (101).

      I guess I haven’t really asked a question – take all of this as an implicit question: is this right? Is this kind of reasoning worth engaging with? Because I for one hardcore disagree with Thagard here (though I generally dig on IBE and I like many of the other things that he points out).

      Note: all of this business of identicalness of course requires a fairly intimate knowledge of the two objects in question: it’s obviously possible that someone might have simply heard the words Hesperus and Phosphorus and not know that they are identical. But if somebody knows that Hesperus is this planet, Venus, and that Phosphorus is this planet, Venus, they cannot fail to know that the two are the same. So assuming we have enough first hand knowledge of what our mind/body is to ‘point’ and say “my mind is this” and “my body is this,” then I think the argument has some force.

    2. You may be right about misinterpretations of the inconceivability argument, but that doesn't completely get at the heart of my problem. I'll try to flesh it out briefly, because I'm also not sure.

      I don't want to take issue with the first proposition of your argument (If proposition x is logically impossible, it is inconceivable) directly, because it seems, by my account, to be true. I think that a square circle is logically impossible.

      My issue is with the degree to which we can be authorities on conceivability, and hence on logical possibility as far as it is related to the former. What if I truly cannot conceive of a situation x, but it turns out that you can? It would be wrong to say that situation x is inconceivable. So the mere fact that someone cannot conceive of something does not make it conceivable.

      There is also the same thing on the other end. We can think that something is conceivable; I can even think that I can personally conceive of it; I can be mistaken about that.

      I'm not going to take an ultimate position on this particular debate, but basically what I would want to say is that someone might say that he can conceive of his mind as not being identical to his body and be wrong about that. And I'm not sure how any degree of argument, or even of introspection, can cure that concern.

    3. At the risk of sounding grumpy, I'm not sure that we should be devoting this much attention to a throw-away line in the only text that I asked you to *skim* for this week. So we can hash it out on the blog instead. First, a disclaimer: I haven't read Chalmers' stuff on conceivability and dualism.

      That being said, I don't think the Hesperus-Phosphorus example actually is a case of *logical* impossibility. In predicate logic, identity relations are simply relations between names, since there is a possible world in which these two names don't stand in an identity relationship, that means that Kripke's point either isn't about logical possibility, or can only be about logical possibility by begging important questions (e.g. by assuming that Hesperus = Venus = Phosphorus is necessarily true, i.e. its negation is logically impossible).

      More to the point however, I don't see how any empirical fact can render something logically impossible. Ex. "P&~P" will be logically impossible regardless of any empirical fact. For this reason, I'm not really sure what the second premise of TS's argument is doing, yet this seems to be the lynchpin given the discussion that follows.

      Instead, I would have thought the following best characterizes the relationship between logical possibility and the existence of facts:

      If proposition x is logically *possible* , then there exists some possible world w containing a fact e that makes x true.

      Here's the problem with dualism: it clearly satisfies the antecedent of this revised conditional, and this means that there is some possible world in which dualism is true. However, this is a shallow victory, since there's also a possible world in which there is a little island in the middle of the Pacific made entirely of Swiss cheese and populated by little purple unicorns.

      So, what we really care about is whether or not the kinds of possible worlds in which dualism is true are similar to our own. Well, how will we decide this? It seems to me that we decide this on the basis of explanatory considerations--does the dualist hypothesis best explain the relevant facts in the actual world? If not, then I take it to be no better than a fanciful hypothesis, only slight less hokey than the purple unicorn one because it explains more facts in the actual world.

      As I said, I steer clear of philosophy of mind, so this should only be read as a comment on TS's post.

  2. Frost-Arnold admits that his (P1) would not be valid if the following statement is true: self-evidencing explanations are rountinely accepted in science. Here Frost-Arnold uses the definition that "an explanation is self-evidencing, only if, at the time of its presentation, the occurrence of the explanandum event provides the only evidence, or an indispensable part of the only evidence, available in support of some of the explanans-statements (44)." My question concerns with the early scientific explanatory approach. Before the establishment of the scientific theories that are commonly accepted now, many of which Frost-Arnold describes as "empirically successful," how did the scientists make progress in their scientific reasoning if self-evidencing explanations were rejected? It seems to me that if we evaluate the validity of a premise by tracing back and questioning its hidden assumptions, we would have to accept at least one self-evidencing explanations at some point. This is because the closer we get back to the beginning of the construction of a theory, the less (empirically successful or logical) background information we have. So in some cases, don't scientists have to accept some self-evidencing explanations in order to make new predictions or unify apparently disparate claims? -- MG

  3. Frost-Arnold's critique of the No-Miracles Argument centers around showing that the NMA itself does not live up to the criteria that scientists usually impose on their own theories. Specifically, he asserts that, like explanans-statements that scientists reject, the NMA fails to "generate new predictions ...[or] unify apparently disparate claims." He then invokes examples of historical theories, including Driesch's Vitalism, Kepler's model of Nested Platonic Solids, and "just-so" evolutionary theories, that were or are rejected on similar grounds.

    Nevertheless, the NMA, stated here as "theories accepted in a mature science are typically approximately true," does not evoke, at least in me, the same sort of dissatisfaction that his examples of other poor theories do. (I can expound on my reasons when we meet, if anyone proves interested.) Even if IBE does not strongly support scientific realism, does the NMA truly not live up to the standard of a scientific explanation? If not, then why does it intuitively feel like a plausible explanation?

    I'm tempted to invoke ideas of coherence when discussing this issue.

  4. Nooooooo.... the comment section ate my comment. Let me attempt to reconstruct it.

    I understand that this might be an obscure point unrelated/tangential to the project of observation or explanation, but I found Sturgeon's reasoning to be lacking, especially in the second section of the essay (p.247-254). In particular, I feel that Sturgeon talks past Harman by using different definitions (e.g., what is moral factness).

    Sturgeon begins by asserting that moral facts are not wholly reducible to physical facts — they supervene in the way that unemployment or GDP is a recognized “real” state of the world. While it may seem that we have settled definitions of unemployment or GDP, each concept/definition is highly contested within the fields of economics and political science. In actuality, there is nothing real about unemployment besides whatever meaning we connote. Sure, it may describe a state of the world, but so does my calling a piece of music “good”, yet I doubt Sturgeon would assent to the reality of aesthetics.

    Instead of some more solid rationale, we must rely on Sturgeon's “confidence” in the coherence and common acceptability of his moral reasoning (249). I personally want some firmer ground to base the reality of morality than a coherent authority (e.g., what if we all agree and have good reason to believe that women have the attribute, “inferior”, as many thought for millennia). Sturgeon claims that if we reject his rejoinder against Harman, we must also in some fundamental way question physical realism as well – i.e., rejection of the former for the reasons Sturgeon gives entails rejection of the later. Yet, Thagard seems to give a fairly decent explanation for physical realism that does not involve or lend credence to moral realism. There is some gulf between physical realism and moral realism that Sturgeon talks his way around.

    Basically, I want to discuss Sturgeon's claim that "morality [is on no] shakier ground than, say, physics" (254).