One of my recurrent interests is confusion, especially in science. The way I understand this concept is as follows: a term or concept is confused = that term or concept takes 2 or more entities to be one entity (where 'entity' covers individual objects, properties, relations, etc.). In other words, a confused concept or term conflates distinct things. I think the phenomenon of confusion is important in science because part of what happens in many scientific revolutions is that, from the point of view of the new scientific framework, the old scientific framework is confused -- or vice versa. (Re: 'vice versa': Einstein's principle of equivalence, for example, would be seen as an unjustified conflation from the viewpoint of a classical physicist: gravitation and inertia are two separate things, and running them together as Einstein does is an unjustified conflation.)
I've recently started looking at another potential case of confusion in science, but I'm a bit uncertain about it, and would like to air it to get reactions.
In high-school biology class, we are told that the highest/ most basic division among life on Earth is between 2 kingdoms: prokaryotes and eukaryotes. Eukaryotes are all those organisms whose genetic material is encapsulated within a nucleus; Prokaryotes are organisms whose genetic material is not. In other words, Prokaryote=df not-Eukaryote.
However, in the last 2-3 decades, the highest taxonomic level has slowly switched to a three-group classification: Eukaryotes, Archaebacteria, and (Eu)bacteria. Why? The short answer is: "on the molecular level, [archaebacteria] resemble other procaryotes, the eubacteria, no more (probably less) than they do the eukaryotes" (C. Woese et al., PNAS 1990 p.4577).
The upshot for present purposes is that there are actually two distinct highest taxa whose genetic material is not enclosed within a nucleus, viz. the archaebacteria and the eubacteria. From this point of view, it appears that 'prokaryote' conflates the archaebacteria and the eubacteria. But if we recall the earlier characterization of 'prokaryote' as simply 'not-eukaryote,' then 'prokaryote' does not appear to be a confused term. So the question is: Is 'prokaryote' confused, or not? (And why?) I'm happy to hear just intuitions, as well as intuitions backed up with some sort of argument or evidence.
P.s. -- For some readers, this discussion will immediately call to mind Quine's solution to the 'grue' paradox in his paper "Natural Kinds" (in Ontological Relativity and other essays). There, Quine notes that if the predicate P picks out a natural kind, then not-P usually doesn't. A hackneyed example: 'gold' picks out a natural kind (any matter with atomic number 79), but 'not-gold' does not, because it covers many, many completely disparate things -- there are too many ways to be not gold for 'not-gold' to refer to a natural kind.
This might make us think that many/ most predicates of the form not-P are, in fact, confused, since such predicates most often apply to many different natural kinds. All I can say at this point is: that sounds counterintuitive to me... it doesn't feel to me like 'not-gold' conflates distinct things.
3/15/2007
3/02/2007
Scott Soames' "Actually" in Vegas
One of my favorite philosophers, Scott Soames, was in Vegas last weekend; he gave a great talk entitled "Actually", and he and his wife Martha took a trip with some of the folks in my department out to the beautiful Valley of Fire state park.
One of the main points Soames pushed was that "actually" plays two very different roles in philosophical semantics. 'Actually p', spoken in a given world W1, means 'p is true in world W1' (sorry, I can't do corner-quotes in Blogger). Now, Soames says there are two ways to specify this world W1:
(1) by picking it out purely indexically, in the way 'I' picks out the speaker of the token, 'now' picks out the moment of utterance, etc. -- so on this way, 'actually p' means 'p is true in THIS world' (or '...in OUR world').
(2) by (roughly- see Soames' paper for the gory details) giving the proposition associated with the Carnapian state-description of W1. (A state-description assigns a value of true or false to every atomic sentence in a language.)
Scott pointed out that if we pick out world W1 in the second way, then 'Actually p' is a priori: once you have a state-description of the world in which that sentence is uttered, then you have all the information you need to figure out its truth-value. This runs contra the conventional wisdom that says 'Actually p' is a posteriori, since we only learn whether p is true in this world via experience; Soames's point was that 'Actually p' is learned via experience when we use way (1) of picking out the world W1, but since there is this other way (2), 'Actually p' is in fact knowABLE a priori, if not knowN a priori in practical cases.
This is very clever, and I need to think more about it, but I think my esteemed colleague James Woodbridge had the best question/ objection of the afternoon. He said 'Actually p' does not just mean 'p is true at world W1,' but rather 'p is true at W1 AND W1 is actual/ instantiated.' Someone could give me the entire state-description of the world we currently inhabit, and then I could calculate from that description that p is true in a world satisfying such a description -- but I still wouldn't know that 'Actually p' is true, because I wouldn't know that the state-description matched this world. (And I was too slow on the uptake to grasp Soames's reply to James.)
My favorite part of Soames's whole talk, though, was the following approximate quotation:
"Perhaps the contingent a priori is just an old wives' tale."
I know I can't get my grandmother to stop talking about Kripke...
One of the main points Soames pushed was that "actually" plays two very different roles in philosophical semantics. 'Actually p', spoken in a given world W1, means 'p is true in world W1' (sorry, I can't do corner-quotes in Blogger). Now, Soames says there are two ways to specify this world W1:
(1) by picking it out purely indexically, in the way 'I' picks out the speaker of the token, 'now' picks out the moment of utterance, etc. -- so on this way, 'actually p' means 'p is true in THIS world' (or '...in OUR world').
(2) by (roughly- see Soames' paper for the gory details) giving the proposition associated with the Carnapian state-description of W1. (A state-description assigns a value of true or false to every atomic sentence in a language.)
Scott pointed out that if we pick out world W1 in the second way, then 'Actually p' is a priori: once you have a state-description of the world in which that sentence is uttered, then you have all the information you need to figure out its truth-value. This runs contra the conventional wisdom that says 'Actually p' is a posteriori, since we only learn whether p is true in this world via experience; Soames's point was that 'Actually p' is learned via experience when we use way (1) of picking out the world W1, but since there is this other way (2), 'Actually p' is in fact knowABLE a priori, if not knowN a priori in practical cases.
This is very clever, and I need to think more about it, but I think my esteemed colleague James Woodbridge had the best question/ objection of the afternoon. He said 'Actually p' does not just mean 'p is true at world W1,' but rather 'p is true at W1 AND W1 is actual/ instantiated.' Someone could give me the entire state-description of the world we currently inhabit, and then I could calculate from that description that p is true in a world satisfying such a description -- but I still wouldn't know that 'Actually p' is true, because I wouldn't know that the state-description matched this world. (And I was too slow on the uptake to grasp Soames's reply to James.)
My favorite part of Soames's whole talk, though, was the following approximate quotation:
"Perhaps the contingent a priori is just an old wives' tale."
I know I can't get my grandmother to stop talking about Kripke...
2/18/2007
Methodological naturalism without metaphysical naturalism
A student of mine pointed out to me this recent New York Times article. It's about Marcus Ross, who recently received his Ph.D. in geology, writing a perfectly normal geology dissertation about what happened 10-15 million years ago -- except this guy is actually a young earth creationist, that is, he believes the Earth is no more than 10,000 years old, based on a literal interpretation of Genesis. Ross says he works within one "paradigm" when writing his dissertation and working within the geological community, but he does not accept this paradigm for all contexts.
A number of interesting things could be said about this (and many are in the NYT article). I wanted to highlight one of the more philosophical aspects of this case. In the context of the debate over Intelligent Design, the anti-evolutionists often say 'Darwinism is a religious belief (perhaps atheism in disguise).' Many pro-evolutionists respond by drawing a distinction between methodological naturalism and metaphysical naturalism, where only the second is anything close to a religious belief. Here's a rough characterization:
(Methodological Naturalism) Scientific explanations cannot appeal to supernatural causes.
(Metaphysical Naturalism) There are no supernatural causes.
The pro-evolutionists say that science only requires methodological naturalism, not the metaphysical naturalism that is pretty close to atheism. So one could be a methodological naturalist, but need not be a metaphysical naturalist (though presumably not vice versa). One natural response the anti-evolutionist could make is that this distinction is contrived, artificial, or otherwise objectionable.
Well, now Marcus Ross is a striking real-life example of someone who is a methodological naturalist without being a metaphysical naturalist. You might think this would make the pro-evolutionists happy -- but as the NYT article makes clear, not all of them are. There are different reasons for this dissatisfaction (e.g., the young earth creationists can now claim this bona fide geologist is on their side). But one thing that perhaps drives the dissatisfaction is that, to quote the student who showed me this article, this person's beliefs seem "crazy". His mental life seems fragmented or segregated in the extreme.
Somewhat ironically, this case appears to serve as a particularly vivid example in favor of the anti-evolutionists' claim that the distinction between methodological and metaphysical naturalism is bogus. On the other hand, in defense of the distinction, perhaps it is not this geologist's metaphysical supernaturalism that makes his stance seem odd, but rather his further beliefs about the particular, specific nature of the divine causes, viz., creating the Earth 10,000 years ago or so.
A number of interesting things could be said about this (and many are in the NYT article). I wanted to highlight one of the more philosophical aspects of this case. In the context of the debate over Intelligent Design, the anti-evolutionists often say 'Darwinism is a religious belief (perhaps atheism in disguise).' Many pro-evolutionists respond by drawing a distinction between methodological naturalism and metaphysical naturalism, where only the second is anything close to a religious belief. Here's a rough characterization:
(Methodological Naturalism) Scientific explanations cannot appeal to supernatural causes.
(Metaphysical Naturalism) There are no supernatural causes.
The pro-evolutionists say that science only requires methodological naturalism, not the metaphysical naturalism that is pretty close to atheism. So one could be a methodological naturalist, but need not be a metaphysical naturalist (though presumably not vice versa). One natural response the anti-evolutionist could make is that this distinction is contrived, artificial, or otherwise objectionable.
Well, now Marcus Ross is a striking real-life example of someone who is a methodological naturalist without being a metaphysical naturalist. You might think this would make the pro-evolutionists happy -- but as the NYT article makes clear, not all of them are. There are different reasons for this dissatisfaction (e.g., the young earth creationists can now claim this bona fide geologist is on their side). But one thing that perhaps drives the dissatisfaction is that, to quote the student who showed me this article, this person's beliefs seem "crazy". His mental life seems fragmented or segregated in the extreme.
Somewhat ironically, this case appears to serve as a particularly vivid example in favor of the anti-evolutionists' claim that the distinction between methodological and metaphysical naturalism is bogus. On the other hand, in defense of the distinction, perhaps it is not this geologist's metaphysical supernaturalism that makes his stance seem odd, but rather his further beliefs about the particular, specific nature of the divine causes, viz., creating the Earth 10,000 years ago or so.
1/20/2007
A difference between science and the humanities?
This post is going to be overly ambitious and overreaching, but isn't that what the blogosphere is all about? Classes started this past week, and I am teaching an upper-level course in philosophy of science. I started the class with the (overly ambitious) question 'What is science?' We had an interesting conversation, and I learned a bit from my students. There was an extended discussion about which particular parts of forensic science really do count as science, and the question 'What is science?' really matters there, because once something is declared accepted science, then it can be admitted into evidence in a court of law.
I had one thought concerning how to distinguish science from the humanities, which I didn't share with my students, but I figured I might try to articulate here. I think it may just be a slightly different way of putting a tired old point, but here goes.
Both the sciences and the humanities seek understanding; both offer explanations of various bits of the world. At a very abstract level, though, the kind of things each tries to explain is different. Obviously, (e.g.) Hamlet is a very different kind of thing than (e.g.) thermometer readings -- I have a more 'formal' difference in mind. When an English professor gives an interpretation of Hamlet, she has (basically: see (3) in next paragraph) ALL the stuff to be explained in front of her: the text is complete, finished. To put the point in terms of evidence instead of explanation, all the data/evidence she can offer for her preferred interpretation of the text is already in. This stands in clear contrast with (most of?) the sciences: new data is constantly being gathered, and new observations need to be explained. If a similar process were occurring in the Hamlet case, a new Act of that play would be produced every week, and various interpretations were shown to be stronger or weaker as new 'data' (i.e. texts) came streaming in.
I think many parts of philosophy are more like the Hamlet case. Take ethics for example. Murder, stealing, lying, etc. are morally wrong. This is in some sense the 'received/ established text' from which the ethicist works: an ethical theory has to explain why those things are wrong. Of course, there are thought-experiments designed to probe various parts of our ethical intuitions, but (1) these often yield contentious/ equivocal results, and (2) more importantly, I only want to say philosophy is more like the Hamlet case, not that it's identical. (Plus, (3) the English professor could potentially get some new information "around the margins" (to put it metaphorically): further historical details of Shakespeare's life, earlier drafts of texts, various facts about the circumstances of production, etc. -- there is clearly a continuum here with absolutely no new data on one end and lots of new data on the other.)
Another philosophical example would be philosophy of arithmetic. We've known that 7+5=12 for some time now, and the philosopher wants to explain how and why we know it's true. We're not getting a whole lot of new 'data' about arithmetic. As a final example, consider the enterprise that falls under the heading of 'interpretation' of various special scientific theories -- an enterprise which is frequently thought of as being particularly close to science. This industry is perhaps most developed in the case of quantum mechanics, but it thrives in general relativity, statistical mechanics, population genetics, etc. as well. On my criterion, these projects (usually) fall much closer to the 'humanities' end of the spectrum: the game here is to take some standard formulation of the theory in question (e.g. of quantum mechanics) and provide an explanation of that theory. The formulation of (e.g.) quantum mechanics is, I think, like the text of Hamlet, insofar as it is taken to exhaust what needs to be explained. However, sometimes this explanation will (either by itself, or with further specification) generate new experimental predictions. When that happens (as in some cases of spontaneous-collapse interpretations of quantum mechanics), then the project becomes more scientific on the above criterion, and less like the humanities.
Perhaps the criterion I've suggested here can partly explain why many (though by no means all!) physicists express exasperation with the philosophy of physics, and consider the enterprise pointless.
I had one thought concerning how to distinguish science from the humanities, which I didn't share with my students, but I figured I might try to articulate here. I think it may just be a slightly different way of putting a tired old point, but here goes.
Both the sciences and the humanities seek understanding; both offer explanations of various bits of the world. At a very abstract level, though, the kind of things each tries to explain is different. Obviously, (e.g.) Hamlet is a very different kind of thing than (e.g.) thermometer readings -- I have a more 'formal' difference in mind. When an English professor gives an interpretation of Hamlet, she has (basically: see (3) in next paragraph) ALL the stuff to be explained in front of her: the text is complete, finished. To put the point in terms of evidence instead of explanation, all the data/evidence she can offer for her preferred interpretation of the text is already in. This stands in clear contrast with (most of?) the sciences: new data is constantly being gathered, and new observations need to be explained. If a similar process were occurring in the Hamlet case, a new Act of that play would be produced every week, and various interpretations were shown to be stronger or weaker as new 'data' (i.e. texts) came streaming in.
I think many parts of philosophy are more like the Hamlet case. Take ethics for example. Murder, stealing, lying, etc. are morally wrong. This is in some sense the 'received/ established text' from which the ethicist works: an ethical theory has to explain why those things are wrong. Of course, there are thought-experiments designed to probe various parts of our ethical intuitions, but (1) these often yield contentious/ equivocal results, and (2) more importantly, I only want to say philosophy is more like the Hamlet case, not that it's identical. (Plus, (3) the English professor could potentially get some new information "around the margins" (to put it metaphorically): further historical details of Shakespeare's life, earlier drafts of texts, various facts about the circumstances of production, etc. -- there is clearly a continuum here with absolutely no new data on one end and lots of new data on the other.)
Another philosophical example would be philosophy of arithmetic. We've known that 7+5=12 for some time now, and the philosopher wants to explain how and why we know it's true. We're not getting a whole lot of new 'data' about arithmetic. As a final example, consider the enterprise that falls under the heading of 'interpretation' of various special scientific theories -- an enterprise which is frequently thought of as being particularly close to science. This industry is perhaps most developed in the case of quantum mechanics, but it thrives in general relativity, statistical mechanics, population genetics, etc. as well. On my criterion, these projects (usually) fall much closer to the 'humanities' end of the spectrum: the game here is to take some standard formulation of the theory in question (e.g. of quantum mechanics) and provide an explanation of that theory. The formulation of (e.g.) quantum mechanics is, I think, like the text of Hamlet, insofar as it is taken to exhaust what needs to be explained. However, sometimes this explanation will (either by itself, or with further specification) generate new experimental predictions. When that happens (as in some cases of spontaneous-collapse interpretations of quantum mechanics), then the project becomes more scientific on the above criterion, and less like the humanities.
Perhaps the criterion I've suggested here can partly explain why many (though by no means all!) physicists express exasperation with the philosophy of physics, and consider the enterprise pointless.
1/15/2007
philosophy on TV
This is not a substantive post, but I wanted to let people know that (1) this blog has not died (yet), and (2) I saw Aristotle quoted in a TV commercial last night. The commercial opened up with Yao Ming (a famous basketball player, for those of you who don't care about such stuff) practicing shooting 18-foot shots, making one after another. Then the screen is replaced with the text: "Excellence is not an act but a habit. --Aristotle"
I think the ad was paid for by the NBA, but I'm not sure. I'm now trying to figure out how to market my own writings to fit various basketball-related themes... I could use the royalties, but I don't see how "Tarski's theory of truth was not motivated by physicalism" or "Developmental biology may not reduce to molecular biology" could tie in with any of the, uh, virtues extolled by basketball culture.
p.s.: Does anyone know why one of Shaquille O'Neal's nicknames is "The Big Aristotle"?
I think the ad was paid for by the NBA, but I'm not sure. I'm now trying to figure out how to market my own writings to fit various basketball-related themes... I could use the royalties, but I don't see how "Tarski's theory of truth was not motivated by physicalism" or "Developmental biology may not reduce to molecular biology" could tie in with any of the, uh, virtues extolled by basketball culture.
p.s.: Does anyone know why one of Shaquille O'Neal's nicknames is "The Big Aristotle"?
12/04/2006
Newton's God
The following three claims from the General Scholium of Newton's Principia have never made sense to me:
One of my students cleverly noted that Newton introduced the notion of a mutually attactive force between every two bodies in the universe; perhaps this can serve as an analogy for a Newton's God, giving me the 'further option' I'm hoping for -- since such a force is neither body nor space nor time? Unfortunately, in that same Scholium, we find an important disanalogy between the universal attractive force and God:
"In him are all things contained and moved, yet neither affects the other: God suffers nothing from the motion of bodies; bodies find no resistance from the omnipresence of God."
Presumably, any supposed force that affects nothing at all is not a force at all.
Are there any other possibilities for helping Newton out?
-----------
p.s. I found the following attempt to save Newton, from my old teacher Ted McGuire, in his "Existence, Actuality and Necessity: Newton on Space and Time," Annals of Science 1978 (how did people do research before the internets?):
"We can plausibly reconstruct the following argument. To say that God is everywhere with respect to space, is to say that one and the same individual exists at each place in extended space. To make such a claim is a contradiction only with respect to the manner in which extended things exist spatially. For they cannot as complete beings exist at once in each "part" of the place they occupy. But there is no contradiction in holding that an essentially non-extended being is capable of so existing. ... God is therefore omnipresent just in the sense that he remains numerically and unalterably the same individual at all places whatsoever. The conception appears paradoxical. However, Newton would claim that it only seems so, if we persist in imagining God's presence in space as we think of bodies individually occupying their determinate places." (p. 506)
But we can't allow ourselves the premise that Newton's God is "an essentially non-extended being," since in the General Scholium, Newton (apparently) says exactly the opposite. (Ted is right that Newton's God is incorporeal, but that isn't the same as non-extended -- think of Newton's absolute space.)
God "is not duration or space, but he endures and is present. He endures forever, and is everywhere present; and by existing always and everywhere, he constitutes duration and space. ... He is utterly void of all body and bodily figure."What I cannot understand is how anything could exist always and everywhere, yet be neither body nor space nor time. Is there some further option for Newton? (Additionally, what does it mean that God 'constitutes' space and time?)
One of my students cleverly noted that Newton introduced the notion of a mutually attactive force between every two bodies in the universe; perhaps this can serve as an analogy for a Newton's God, giving me the 'further option' I'm hoping for -- since such a force is neither body nor space nor time? Unfortunately, in that same Scholium, we find an important disanalogy between the universal attractive force and God:
"In him are all things contained and moved, yet neither affects the other: God suffers nothing from the motion of bodies; bodies find no resistance from the omnipresence of God."
Presumably, any supposed force that affects nothing at all is not a force at all.
Are there any other possibilities for helping Newton out?
-----------
p.s. I found the following attempt to save Newton, from my old teacher Ted McGuire, in his "Existence, Actuality and Necessity: Newton on Space and Time," Annals of Science 1978 (how did people do research before the internets?):
"We can plausibly reconstruct the following argument. To say that God is everywhere with respect to space, is to say that one and the same individual exists at each place in extended space. To make such a claim is a contradiction only with respect to the manner in which extended things exist spatially. For they cannot as complete beings exist at once in each "part" of the place they occupy. But there is no contradiction in holding that an essentially non-extended being is capable of so existing. ... God is therefore omnipresent just in the sense that he remains numerically and unalterably the same individual at all places whatsoever. The conception appears paradoxical. However, Newton would claim that it only seems so, if we persist in imagining God's presence in space as we think of bodies individually occupying their determinate places." (p. 506)
But we can't allow ourselves the premise that Newton's God is "an essentially non-extended being," since in the General Scholium, Newton (apparently) says exactly the opposite. (Ted is right that Newton's God is incorporeal, but that isn't the same as non-extended -- think of Newton's absolute space.)
11/20/2006
Newton and Wittgenstein -- long lost cousins?
As I was preparing for my History of Scientific Thought class tomorrow, I noticed the following line in Newton's Principia: "the meaning of words is to be determined by their use." (It's in the 14th paragraph of the Scholium to the Definitions, if anyone cares.) This is a revolution in Wittgenstein historiography! We obviously need to re-write all the history textbooks: Wittgenstein should no longer be seen as making a radical break with tradition, but rather advocating a return to orthodox Newtonianism...
But seriously: does anyone else know of other clean expressions of the Wittgensteinian 'meaning is use' slogan in the centuries before Wittgenstein?
But seriously: does anyone else know of other clean expressions of the Wittgensteinian 'meaning is use' slogan in the centuries before Wittgenstein?
11/18/2006
Intelligibility in 17th and 20th century scientific philosophy
Should scientific theories be understandable -- or at least, aim at understandability? Of course, the term 'understandable' is vague and/or ambiguous, perhaps so much so that this question is some combination of pointless and unanswerable. But let's suppose the concept of understandability (or, equivalently, intelligibility) is sufficiently determinate.
One might think that understandability is not a standard on scientific claims. Sure, it's nice when we can have it; but as certain physicists say, 'Nobody really understands quantum mechanics.' On this view, evidence can justify a theory to a sufficient degree to motivate acceptance of that theory, even if that theory is (in some sense) not completely intelligible.
I don't know what the answer to this question is. But I was recently struck by a similarity between the mechanical philosophers of the middle 17th C and the logical empiricists of the early 20th C. In The World, Descartes says he will describe a universe that only has properties that everyone, even the dense, can fully understand (viz., the shape, size and motion of matter). In "On the Grounds and Excellency of the Mechanical Hypothesis," Robert Boyle claims that one of the advantages of the mechanical philosophy over that of the Peripatetics and the Paracelsian chemists is that the mechanical philosophy only uses terms understood clearly by everybody. The idea is that the word 'cube' will call up the same idea for everyone, whereas 'substantial form' (Peripatetics) or 'active principle' (Chemists) will not. Just about everyone can agree on whether a particular thing is cubical or not -- we will enjoy less agreement about whether a particular substance contains an active principle or not... or about what an active principle is, exactly.
What I now recognize is that certain aspects of logical empiricism have very much the same spirit. For Carnap, Neurath, and other logical empiricists, one of the primary aims of the language reforms they proposed was to guarantee the intelligibility or understandability of sentences that aim to state facts. Neurath proposed the adoption of a 'Universal Jargon' that was supposed to be a refinement of everyday language; Carnap proposed various types of languages at various points in his career -- the language of sense perception was the most fully developed in the Aufbau, and the language of middle-sized dry goods was preferred after that. Why these languages? Because, in each case, such sentences were supposed to be the most paradigmatically or obviously meaningful sentences; if (e.g.) everyday language is not meaningful, then nothing is. Furthermore, these sentences mean the same thing (or close) to all competant speakers; Philipp Frank, for instance, embraced such language-reform projects in order to counteract the Tower of Babel-esque proliferation of jargons in various scientific sub-disciplines.
I think further parallels between the 17th and early 20th C philosophers can be tied into this issue: both groups want to unify science (though in different ways, I think) and to eliminate the excessive metaphysical speculations of their respective times. I think the impetus toward intelligibility, in both cases, drives (at least in part) these other programs.
One might think that understandability is not a standard on scientific claims. Sure, it's nice when we can have it; but as certain physicists say, 'Nobody really understands quantum mechanics.' On this view, evidence can justify a theory to a sufficient degree to motivate acceptance of that theory, even if that theory is (in some sense) not completely intelligible.
I don't know what the answer to this question is. But I was recently struck by a similarity between the mechanical philosophers of the middle 17th C and the logical empiricists of the early 20th C. In The World, Descartes says he will describe a universe that only has properties that everyone, even the dense, can fully understand (viz., the shape, size and motion of matter). In "On the Grounds and Excellency of the Mechanical Hypothesis," Robert Boyle claims that one of the advantages of the mechanical philosophy over that of the Peripatetics and the Paracelsian chemists is that the mechanical philosophy only uses terms understood clearly by everybody. The idea is that the word 'cube' will call up the same idea for everyone, whereas 'substantial form' (Peripatetics) or 'active principle' (Chemists) will not. Just about everyone can agree on whether a particular thing is cubical or not -- we will enjoy less agreement about whether a particular substance contains an active principle or not... or about what an active principle is, exactly.
What I now recognize is that certain aspects of logical empiricism have very much the same spirit. For Carnap, Neurath, and other logical empiricists, one of the primary aims of the language reforms they proposed was to guarantee the intelligibility or understandability of sentences that aim to state facts. Neurath proposed the adoption of a 'Universal Jargon' that was supposed to be a refinement of everyday language; Carnap proposed various types of languages at various points in his career -- the language of sense perception was the most fully developed in the Aufbau, and the language of middle-sized dry goods was preferred after that. Why these languages? Because, in each case, such sentences were supposed to be the most paradigmatically or obviously meaningful sentences; if (e.g.) everyday language is not meaningful, then nothing is. Furthermore, these sentences mean the same thing (or close) to all competant speakers; Philipp Frank, for instance, embraced such language-reform projects in order to counteract the Tower of Babel-esque proliferation of jargons in various scientific sub-disciplines.
I think further parallels between the 17th and early 20th C philosophers can be tied into this issue: both groups want to unify science (though in different ways, I think) and to eliminate the excessive metaphysical speculations of their respective times. I think the impetus toward intelligibility, in both cases, drives (at least in part) these other programs.
10/23/2006
On the Darwinian explanation of the success of science
I really don't have time to post now, but I'm going to anyway. Van Fraassen writes: "I claim that the success of current scientific theories is no miracle. It is not even surprising to the scientific (Darwinian) mind. For any scientific theory is born into a life of fierce competition, a jungle red in tooth and claw. Only the successful theories survive--the ones which in fact latched on to actual regularities in nature." (Scientific Image, p.40)
James Robert Brown, in "Explaining the Success of Science" (Ratio, 1985) agrees that this Darwinian explanation can account for the first two aspects of success, but not the third:
(1) The sciences "are able to organize and unift a great variety of known phenomena.
(2) This ability to systematize the empirical data is more extensive now than it was for previous theories.
(3) A statistically significant number of novel predictions pan out; that is, our theories get more predictions right than mere guessing would allow." Brown says of (3): "Here the Darwinian analogy breaks down since most species could not survive a radical change of environment, the analogue of a novel prediction."
First a small point: I don't think a novel prediction needs to be analogized to a radical change in environment -- perhaps some should be, but it's not necessary. If an organism can handle living and reproducing in any new environment, i.e., one for which its various features were not historically adapted, then that seems a decent enough analogy to a novel prediction (which makes a prediction different from the cases the thoery was originally designed to handle). A 'radical' change in environment might precipitate a scientific revolution -- i.e., the science (like the organism) might not survive.
Now, a more substantive point, and one which perhaps pushes the analogy farther than is fair. The paleobiologist David Jablonski has shown that genera that are more geographically widespread are more likely to survive mass extinction events (such as the meteor that killed off lots of the dinosaurs). The analogy would be, I suppose, to groups of related theories that 'organize and unify' a greater variety of phenomena -- which are precisely the groups of theories that we (including van Fraassen) count as most successful. So it appears that a van Fraassenite Darwinian has a nice answer to J.R. Brown: viz., the more successful groups of theories will be more likely to deliver novel predictions.
But unfortunately for the van Fraassenite, the biological story doesn't end there. What is strange about Jablonski's results is that a species' being geographically widespread has no statistical correlation with its probability of surviving a mass extinction event. The correlation only appears at the level of genera. (Side note: For the philosophers and biologists who think about group selection, this looks like an instance of it.) So, the analogy would go, the more unifying particular theories do not enjoy any advantage in novel prediction over the less unifying, but the more unifying groups of theories would. Hopefully you can see why I suggested that this may be pushing the analogy too far: I'm not sure there's anything in the domain of science that would correspond nicely to the concepts of genus and species in the evolutionary domain. Although (and now I'm really stretching), if one could be made out, perhaps the structural realists could cash out their notion of structure at the level of the genus, and thereby capture why particular theories come and go, but the structure tends to survive through revolutions.
p.s. -- Can anyone recommend a good article completely devoted to arguing for or against this Darwinian explanation of science's success? I've seen several parts of book chapters or parts of papers dealing with it, but I can't recall seeing a fine-tooth-comb analysis of it.
James Robert Brown, in "Explaining the Success of Science" (Ratio, 1985) agrees that this Darwinian explanation can account for the first two aspects of success, but not the third:
(1) The sciences "are able to organize and unift a great variety of known phenomena.
(2) This ability to systematize the empirical data is more extensive now than it was for previous theories.
(3) A statistically significant number of novel predictions pan out; that is, our theories get more predictions right than mere guessing would allow." Brown says of (3): "Here the Darwinian analogy breaks down since most species could not survive a radical change of environment, the analogue of a novel prediction."
First a small point: I don't think a novel prediction needs to be analogized to a radical change in environment -- perhaps some should be, but it's not necessary. If an organism can handle living and reproducing in any new environment, i.e., one for which its various features were not historically adapted, then that seems a decent enough analogy to a novel prediction (which makes a prediction different from the cases the thoery was originally designed to handle). A 'radical' change in environment might precipitate a scientific revolution -- i.e., the science (like the organism) might not survive.
Now, a more substantive point, and one which perhaps pushes the analogy farther than is fair. The paleobiologist David Jablonski has shown that genera that are more geographically widespread are more likely to survive mass extinction events (such as the meteor that killed off lots of the dinosaurs). The analogy would be, I suppose, to groups of related theories that 'organize and unify' a greater variety of phenomena -- which are precisely the groups of theories that we (including van Fraassen) count as most successful. So it appears that a van Fraassenite Darwinian has a nice answer to J.R. Brown: viz., the more successful groups of theories will be more likely to deliver novel predictions.
But unfortunately for the van Fraassenite, the biological story doesn't end there. What is strange about Jablonski's results is that a species' being geographically widespread has no statistical correlation with its probability of surviving a mass extinction event. The correlation only appears at the level of genera. (Side note: For the philosophers and biologists who think about group selection, this looks like an instance of it.) So, the analogy would go, the more unifying particular theories do not enjoy any advantage in novel prediction over the less unifying, but the more unifying groups of theories would. Hopefully you can see why I suggested that this may be pushing the analogy too far: I'm not sure there's anything in the domain of science that would correspond nicely to the concepts of genus and species in the evolutionary domain. Although (and now I'm really stretching), if one could be made out, perhaps the structural realists could cash out their notion of structure at the level of the genus, and thereby capture why particular theories come and go, but the structure tends to survive through revolutions.
p.s. -- Can anyone recommend a good article completely devoted to arguing for or against this Darwinian explanation of science's success? I've seen several parts of book chapters or parts of papers dealing with it, but I can't recall seeing a fine-tooth-comb analysis of it.
10/07/2006
Aristotle's natural motion and modern inertial motion
Last week, in my history of science class, we finished the unit on ancient science and medicine. At the end of the unit, I asked my students the (ill-posed) question: so is any of this stuff we've been reading science or not? (We read Plato's Timaeus, Aristotle's Physics II and On the Heavens, Ptolemy's Almagest, and bits of Epicurus as well as Hippocratic writers.)
One sentiment that came to the fore was that the ancients were (on average) more willing to countenance teleological explanations in natural sciences than we are. I think this is definitely right on the whole. But I did want to ask a question about an example sometimes forwarded in defense of this claim. Aristotle says that part of what makes the element earth earth is its tendency to move towards the center of the universe (since Aristotle thought the planet Earth was at rest in the center of the universe). Air and fire move away from the center of the universe, and the celestial matter moves in a circle around the center. These 'natural motions' are taken to appeal to final causes in a way that modern science does not: water and earth have a 'goal' or 'end' (Greek telos), viz., the center of the universe. And (so the story goes) matter from the Early Modern period onwards, starting with Descartes at the latest, is not like that at all.
I, unfortunately, cannot make out a substantive difference here -- we can describe Aristotle and the moderns in the same terms: we can make Aristotle sound more modern, or make Newton et al. sound more teleological. In the modern dynamical picture, we have inertial motion: a body in motion will maintain that motion (speed and direction), unless acted upon by an outside force. If the telos of an Aristotelian hunk of earth is the center of the universe, the telos of a modern bit of matter is (something like) self-preservation. Its goal is resistance to change (of direction and speed).
Alternatively, we can characterize Aristotle as more modern: Aristotle is describing what happens to a bit of fire or water if it's just "left alone," i.e., what does a body do when it is free of any interference? Aristotle clearly disagrees with the moderns about what a body does when "left alone"... but Einstein disagreed with Newtonians over the same issue. In other words, we can think of the difference (on this topic) between Aristotle and the moderns as a disagreement over which trajectories are the ones bodies will follow when no external forces act upon them. Teleology doesn't appear here at all.
Of course, I could be overlooking something obvious in the Aristotelian text. Hopefully any real Aristotle scholars out there reading this will tell me if I have. If you want to check the text of On the Heavens for yourself, it’s online here.
One sentiment that came to the fore was that the ancients were (on average) more willing to countenance teleological explanations in natural sciences than we are. I think this is definitely right on the whole. But I did want to ask a question about an example sometimes forwarded in defense of this claim. Aristotle says that part of what makes the element earth earth is its tendency to move towards the center of the universe (since Aristotle thought the planet Earth was at rest in the center of the universe). Air and fire move away from the center of the universe, and the celestial matter moves in a circle around the center. These 'natural motions' are taken to appeal to final causes in a way that modern science does not: water and earth have a 'goal' or 'end' (Greek telos), viz., the center of the universe. And (so the story goes) matter from the Early Modern period onwards, starting with Descartes at the latest, is not like that at all.
I, unfortunately, cannot make out a substantive difference here -- we can describe Aristotle and the moderns in the same terms: we can make Aristotle sound more modern, or make Newton et al. sound more teleological. In the modern dynamical picture, we have inertial motion: a body in motion will maintain that motion (speed and direction), unless acted upon by an outside force. If the telos of an Aristotelian hunk of earth is the center of the universe, the telos of a modern bit of matter is (something like) self-preservation. Its goal is resistance to change (of direction and speed).
Alternatively, we can characterize Aristotle as more modern: Aristotle is describing what happens to a bit of fire or water if it's just "left alone," i.e., what does a body do when it is free of any interference? Aristotle clearly disagrees with the moderns about what a body does when "left alone"... but Einstein disagreed with Newtonians over the same issue. In other words, we can think of the difference (on this topic) between Aristotle and the moderns as a disagreement over which trajectories are the ones bodies will follow when no external forces act upon them. Teleology doesn't appear here at all.
Of course, I could be overlooking something obvious in the Aristotelian text. Hopefully any real Aristotle scholars out there reading this will tell me if I have. If you want to check the text of On the Heavens for yourself, it’s online here.
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