Scientific explanations, which explain the behavior of an actual object by relating it to the behavior of an ideal object, don't usually involve a normative element. It's not as if we think that inclined planes should be frictionless, or planets should be perfectly spherical. These ideal models aren't somehow better then the actual objects in question, they are just easier to think about.
I wonder if psychological explanations of actual human behavior by relating it to rational human behavior ("the price rises because if everyone was a homo economicus with this set of beliefs and desires they would..." "actually, getting a beer is what a fully rational person with Jim's beliefs and desires would do right now..") are just instances of this. If they are, then the normativity makes no difference to the explanation. The idea that one ought to be rational (assuming there is such a fact) plays no more role in the success of the explanation than the claim that inclined planes ought to be frictionless plays in the success of the ordinary physical explanation.
Showing posts with label explanation. Show all posts
Showing posts with label explanation. Show all posts
Tuesday, March 16, 2010
Sunday, February 21, 2010
Explanation Puzzle
On the one hand, we think that the fact that a theory T1 allows for "better explanation" of a certain phenomena than T2, gives us reason to believe T1 rather than T2 is correct. It's obvious (if not particularly explanatory) reason to prefer one theory to another that it "does a better job of explaining the data"!
On the other hand, we think that a better explanation can be one that better helps human beings "grock" patterns in the behavior of physical systems which may be mathematically very complex. Given human psychology, attention span etc. a simple ceterus paribus statement about struck matches tending to light can be a better explanation than an explanation that appeals to more specific details. To choose a more extreme example, even if there were a completely successful theory of microphysics, most people feel we would still have an explanatory task. We would still want elegant theories that told us about general high-level patterns in how the microphysical facts would evolve forward through time. (e.g. the ideal gas law, biology and maybe psychology and economics).
But now here's the problem: do we really think that the fact that a theory T allows for nice tractable/human-grockable explanations of high level phenomena makes it more likely to be true? For example:
I find "consider a spherical cow" style economics explanation, or "consider philosophers building up society from a state of nature" style early modern philosophy explanations way more attractive, satisfying, and easy to remember than explanations that cite lots of boring contingent historical facts. But this doesn't really make me feel that these explanations are more plausible, or getting at the heart of matters more.
I mean, I wouldn't be surprised if primate intelligence is optimized for avoiding getting double crossed by other monkeys, and making practical plans etc. so we like explanations better if they relate the explananda to these things (i.e, people with plans). Indeed don't we actually find this with explaining a phenomenon to people in different disciplines- that people familar with different areas find different explanations more satisfying?
We like explanations where lots of correct consequences "fall out immediately" from a tiny theory. But what seems to fall out immediately (vs. just be an ugly mathematical consequence) may well depend on how familiar you are with inferences of that kind. And folk (belief/desire) psychology is something we are *all* very familiar with from daily life. Hence, when someone says "this electron wants to escape the other electron" or "countries covet land", we have lots of immediate ideas about what behavior should follow from that, because we are experts at drawing consequences from belief desire psychology, and then we just convert these consequences back to the task at hand.
But surely allowing for nice parallels to common problems in monkey social climbing, is not a feature that has much to do with genuine theoretical elegance/ how likely a theory is to be correct.
On the other hand, we think that a better explanation can be one that better helps human beings "grock" patterns in the behavior of physical systems which may be mathematically very complex. Given human psychology, attention span etc. a simple ceterus paribus statement about struck matches tending to light can be a better explanation than an explanation that appeals to more specific details. To choose a more extreme example, even if there were a completely successful theory of microphysics, most people feel we would still have an explanatory task. We would still want elegant theories that told us about general high-level patterns in how the microphysical facts would evolve forward through time. (e.g. the ideal gas law, biology and maybe psychology and economics).
But now here's the problem: do we really think that the fact that a theory T allows for nice tractable/human-grockable explanations of high level phenomena makes it more likely to be true? For example:
I find "consider a spherical cow" style economics explanation, or "consider philosophers building up society from a state of nature" style early modern philosophy explanations way more attractive, satisfying, and easy to remember than explanations that cite lots of boring contingent historical facts. But this doesn't really make me feel that these explanations are more plausible, or getting at the heart of matters more.
I mean, I wouldn't be surprised if primate intelligence is optimized for avoiding getting double crossed by other monkeys, and making practical plans etc. so we like explanations better if they relate the explananda to these things (i.e, people with plans). Indeed don't we actually find this with explaining a phenomenon to people in different disciplines- that people familar with different areas find different explanations more satisfying?
We like explanations where lots of correct consequences "fall out immediately" from a tiny theory. But what seems to fall out immediately (vs. just be an ugly mathematical consequence) may well depend on how familiar you are with inferences of that kind. And folk (belief/desire) psychology is something we are *all* very familiar with from daily life. Hence, when someone says "this electron wants to escape the other electron" or "countries covet land", we have lots of immediate ideas about what behavior should follow from that, because we are experts at drawing consequences from belief desire psychology, and then we just convert these consequences back to the task at hand.
But surely allowing for nice parallels to common problems in monkey social climbing, is not a feature that has much to do with genuine theoretical elegance/ how likely a theory is to be correct.
On Rationalizing Explanations
Philosophy papers (like David Lewis' Languages and Language) often seem to want to explain the fact that some X is actually the case (e.g. we all use the word "fire" in roughly the same ways) by showing why it would be rational for people to make X the case/preserve that state of affairs X. But this seems potentially problematic:
a) Historians wouldn't generally accept the idea that showing why declaring war was rational for a certain leader explains why he actually did declare war. If the presedent has the policy of always taking the first proposal suggested when he's tired and wants to go home, and P was the first proposal suggested, the fact that it would be rational to do P rather than Q is not the correct explanation for why the president actually did P rather than Q. Similarly if the president never even considered Q, the fact that P serves his interests better than Q seems like an incorrect explanation for his choosing Q.
b) More generally, rationality explanations seem to have exactly the issues that philosophers of biology make a huge deal about when considering evolutionary fitness explanations: the mere fact that some trait would be eliminated by natural selection isn't always the correct explanation for why we don't find it. For example, the fact that humans don't levitate isn't explained by natural selection, but rather by the fact that the total space of mutations available from the original organisms doesn't include that. (That is: plausibly, even if all creatures had had all the offspring they could, and lived as long as they could so there was no culling to generate natural selection, we would *still* find 0 creatures that levitate. )
Applied to the David Lewis case of conventions, this works out in the following way. It *might* be that we get linguistic conventions because once some people are using language a given way, each person works out that it would be rational for them to do the same (this is the nub of lewis' account). Or it might be that most possibilities for doing things differently don't even occur to them - people just brutely follow custom and habit and imitate those around them. (Apparently apes' tool use is like this: chimps in a given area all crack nuts using the same techniques, even though different techniques would work just as well and are used in different areas. Note here that there's no rational benefit to cracking nuts differently from your neighbor). Or it might be some combination of habit plus considerations of rationality. And surely its an empirical matter to find out which.
Given this, I think we can read Lewis either as making a bold empirical conjecture, or as explaining actual behavior by comparing it to the behavior of a simpler, but in some respects similar, model system (as often happens in biology).
bold empirical conjecture: In fact, adherence to linguistic conventions is always produced, not by custom and habit whereby doesn't occur to people to behave otherwise, but by speakers recognizing that it would be rational for them to continue with the convention.
simplified model system explanation: In ideal system S (where there are no limitations on computational power etc and people always behave in the way that best advances their aims), linguistic conventions arise and persist. The actual world of people talking is `relevantly similar enough' to S, for these facts about S to explain how actual linguistic conventions arise and persist in the actual world. [Slot in whatever notion of relevantly similar explains how facts about waves in infinitely deep oceans can explain facts about waves in actual finitely deep oceans].
a) Historians wouldn't generally accept the idea that showing why declaring war was rational for a certain leader explains why he actually did declare war. If the presedent has the policy of always taking the first proposal suggested when he's tired and wants to go home, and P was the first proposal suggested, the fact that it would be rational to do P rather than Q is not the correct explanation for why the president actually did P rather than Q. Similarly if the president never even considered Q, the fact that P serves his interests better than Q seems like an incorrect explanation for his choosing Q.
b) More generally, rationality explanations seem to have exactly the issues that philosophers of biology make a huge deal about when considering evolutionary fitness explanations: the mere fact that some trait would be eliminated by natural selection isn't always the correct explanation for why we don't find it. For example, the fact that humans don't levitate isn't explained by natural selection, but rather by the fact that the total space of mutations available from the original organisms doesn't include that. (That is: plausibly, even if all creatures had had all the offspring they could, and lived as long as they could so there was no culling to generate natural selection, we would *still* find 0 creatures that levitate. )
Applied to the David Lewis case of conventions, this works out in the following way. It *might* be that we get linguistic conventions because once some people are using language a given way, each person works out that it would be rational for them to do the same (this is the nub of lewis' account). Or it might be that most possibilities for doing things differently don't even occur to them - people just brutely follow custom and habit and imitate those around them. (Apparently apes' tool use is like this: chimps in a given area all crack nuts using the same techniques, even though different techniques would work just as well and are used in different areas. Note here that there's no rational benefit to cracking nuts differently from your neighbor). Or it might be some combination of habit plus considerations of rationality. And surely its an empirical matter to find out which.
Given this, I think we can read Lewis either as making a bold empirical conjecture, or as explaining actual behavior by comparing it to the behavior of a simpler, but in some respects similar, model system (as often happens in biology).
bold empirical conjecture: In fact, adherence to linguistic conventions is always produced, not by custom and habit whereby doesn't occur to people to behave otherwise, but by speakers recognizing that it would be rational for them to continue with the convention.
simplified model system explanation: In ideal system S (where there are no limitations on computational power etc and people always behave in the way that best advances their aims), linguistic conventions arise and persist. The actual world of people talking is `relevantly similar enough' to S, for these facts about S to explain how actual linguistic conventions arise and persist in the actual world. [Slot in whatever notion of relevantly similar explains how facts about waves in infinitely deep oceans can explain facts about waves in actual finitely deep oceans].
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