Monday, December 10, 2007
Davies and Materialism
Friday, December 7, 2007
Dimensional Folding and Coherence
There is some rather interesting work in cognitive psychology and psycholinguistics on the relationship between writing styles and reader uptake. Specifically, the construction-integration model by Walter Kintsch and others tries to tease out how information learning is modulated by the learner's pre-existing cognitive model. There is a bit of parallelism with "constructivism" in educational circles that postulates that learning is a process of building, tearing down and re-engineering cognitive frameworks over time, requiring each student to be uniquely understood as bringing pre-existing knowledge systems to the classroom.
In construction-integration theory, an odd fact has been observed: if a text has lots of linking words bridging concepts from paragraph to paragraph, those with limited understanding of a field can get up to speed with greater fluidity than if the text is high-level and not written with that expectation in mind. In turn, those who are advanced in the subject matter actually learn faster when the text is more sparse and the learner bridges the gaps with their pre-existing mental model.
We can even measure this notion of textual coherence or cohesion using some pretty mathematics. If we count all the shared terms from one paragraph to the next in a text and then try to eliminate the noisy outliers, we can get a good estimate of the relative cohesion between paragraphs. These outliers arise due to lexical ambiguity or because many terms are less semantically significant than they are syntactically valuable.
A singular value decomposition (SVD) is one way to do the de-noising. In essence, the SVD is an operation that changes a large matrix of counts into a product of three matrixes, one of which contains "singular values" along the matrix diagonal. We can then order those values by magnitude and eliminate the small ones, then re-constitute a version of the original matrix. By doing this, we are in effect asking which of the original counts contribute little or nothing to the original matrix and eliminating those less influential terms.
There are some other useful applications of this same principle (broadly called "Latent Semantic Analysis" or LSA). For instance, we can automatically discover terms that are related to one another even though they may not co-occur in texts. The reduction and reconstitution approach, when applied to the contexts in which the terms occur, will tend to "fold" together contexts that are similar, exposing the contextual similarity of terms. This has applications in information retrieval, automatic essay grading and even machine translation. For the latter, if we take "parallel" texts (texts that are translations of one another by human translators), we can fold them all into the same reduced subspace and get semantically-similar terms usefully joined together.
Terence Yao's presentation is clearly aimed at grad students, advanced undergrads and other mathematics professionals, so his language tends to be fairly non-cohering (not, I note, do I think he incoherent!), and much of the background is left out or is connected via Wikipedia links. The links are a nice addition that is helpful to those of us not active in the field, and a technique that provides a little more textual cohesion without unduly bothering the expert.
Saturday, November 24, 2007
Multiverses and Regress
D’Souza’s flaw is primarily in his historical dismissal of the achievements of other cultures, like Islam, in the development of math and science. In his presentations and articles he tends to quote a single Islamic philosopher who believed that Allah could be as irrational as he wanted to be, as if that led all Islamic thinkers to dismiss as impossible any understanding of the universe beyond the ideas of the Koran. Of course we know that was not the case, and hence we get algebra through Aldebaron.
Ptolemy, Pythagoras, Democritus and Epicurus would be similarly shocked by D'Souza's claims.
Davies’ error is in his assumption that science must be a closed intellectual system, thus submitting the entire explanatory framework to an argument of infinite regress. If we see symmetry in forces, there must be an explanation for that symmetry. Then we need an explanation beyond that symmetry. If we assume that the existing laws are effective explanations, he declares that we have invoked faith that has the same essential character as the faith of the religious.
This, of course, dismisses the entire project of inference and abduction—the contingency of liberal rationalism—using a logical positivist conception of theory. We do not, as Davies declares, claim scientifically that there may be no explanation for the ordered nature of physical law. We simply hold that there is no clear theoretical construct and supporting evidence to provide such an explanation. We keep looking and constantly ask ourselves: are there any exceptions to relativistic conceptions of gravitation? We look for anomalous disconfirmation because it leads to conceptual revision. We tentatively hold forth multiple universes and ask whether there is any way to confirm or refute the idea, or whether the idea has consequences.
That, to my mind, is nothing like religious faith, and is only loosely allied with the grand ordered Deism of Newton.
Friday, November 23, 2007
Math, Science and Popular Culture
That was just over a year ago and my evening productivity has suffered. I spent probably six months just exploring features, programming a universal remote and capturing programming. Then I settled in to watch some specific programs in addition to movies and documentaries.
There are four network programs that I want to mention because of their unexpected cultural importance: the CSI franchise, House, Numb3rs and Criminal Minds. In each case, science or mathematics plays an essential role. In each case, the background material is actually well-researched, although the outcomes are almost always ridiculously neat in order to fit the format.
Numb3rs is the show closest to my background in terms of using algorithms and mathematics to solve problems. In a recent show, in fact, one mathematician used a classification and regression tree (CART) algorithm to do something. I’ve used CART before. Some of the other topics in social network analysis and covering algorithms also ring vaguely true, though they are distorted through a lens of excited elaboration that gets tiresome over time.
Northeastern University keeps track of some of the Numb3rs mathematics, here.
But more important, I think, is the cultural message that intelligent people with highly developed skill sets are heroes. Even Gregory House is a hero of sorts in his coldly analytical pursuit of truth, his anti-theism and dedication to correct diagnoses. I contrast this kind of programming with 90210, Dallas or other cultural phenomena that seemed to cater to baser ideas of wealth, power and privilege. Is the brain on the rise?
I have to admit that I am getting some kind of network television fatigue here after a year with the DVR and shows are stacking up on the hard drive. I may have to go back to a stricter media diet, but hope the science and math keeps a place on the television menu.
Wednesday, November 14, 2007
Folksonomics and Conceptual Metadata
Health care reform is, of course, a deeply political topic that breaks down along several ideological and interest dimensions. In supporting the claims for all sides, basic research is mined and often cherry-picked to build a case. And my point in this entry is not to make an ideological or political claim but to describe in a way how that information is discovered, used and reused.
Now I was quite a novice on the topic of health care economics and reform ideas when I began researching the topic. I certainly had personal negative and positive experiences over the years. I also had heard the reviews and blowback over Michael Moore’s Sicko (though have not yet seen the film). But, beyond that, I had no real understanding of who the players were, what the research suggested, or what the counterclaims were.
My understanding built from a range of sources, most of which were simply not accessible even a decade ago to casual researchers like me. Instead, you had to be a Beltway insider who subscribed to think tank newsletters and research publications. But now I can download and read Commonwealth Fund reports, CATO news briefs, and a host of other resources and become a moderately well-informed amateur researcher. I can access huge swaths of blogs and commentary, reflecting different perspectives. I can even organize the information by collecting it together and then labeling it for easy recovery based on a recollection.
What I can’t easily do yet is to be able to answer specific questions that have not already been answered in some publication, but that emerge out of the collected information. For example, after I read how the German medical system did not have the kinds of rationing and waits for access that we associate with certain aspects of the British and Canadian systems in a Commonwealth Fund report, I wanted to know the details of the German system. Was it a single-payer or nationalized health service? Perhaps a hybrid? What was the role of doctors and information technology? It took quite a lot of searching to finally be able to answer those questions, ultimately using a Siemens Medical Technology prĂ©cis and market analysis of the German system.
Could approaches like structured metadata via Semantic Web technologies assist me in these tasks? Perhaps, but it seems to require that propositional information above the level of named entity extraction could be accurately indexed. For the first question, I would need documents labeled with “Structure of the German Medical System” or the equivalent rather than the many nuanced and varied ways that we write. Moreover, the proposition needs to express the timeliness of the resource, a problem I frequently encounter when trying to fix problems with my Linux computers. How timely is a given piece of information?
We can’t, however, expect individuals to be able to code that metadata in any consistent way, though I believe there is a folksonomic method that can lend a hand: a community of users can gradually improve the metadata structure and content in much the same way that Wikipedia is gradually improved. The Wikipedia model has also shown that quality can be maintained—with fits and starts—by a community of users and some policies in place.
Friday, November 2, 2007
Leftward and Magical Thinking
So where to start?
There is a remarkable literature on the relationship between magical thinking and schizophrenic behavior. Not surprisingly, schizotypic ideation (delusional psychotic thoughts) correlates with magical thinking indexes. So, if you believe in mystical connections throughout the universe, you might also believe that forces are communicating with you.But the connections are more interesting, still. If you ask people to grade the relationship between different words on a 1-5 scale, with 1 indicating the words are unrelated and 5 meaning they are nearly identical, people who rate highly on magical thinking indexes also tend to rate unrelated words more related than those with low index ratings.
And it is the right hemisphere action that results in the tendency to turn left because the right hemisphere controls left motor functions. So those with schizophrenia, those who damage their brains with amphetamines, and those with magical thinking tendencies will veer a bit left when asked to mark the center of a piece of paper. At the extreme, Parkinson’s patients with extreme dopamine issues will wander in leftward arcs. So will rats.
Leftward, always leftward. The artists all lingered to the left while finding patterns where the rest of us found only randomness. It is the source of gurus and mystics, artists and poets, and, perhaps, NASCAR drivers.
Sunday, October 28, 2007
Mind and Connectivity
I lamented this recently when my Casio atomic solar watch died due to the gumming up of the backlight button from too much swimming, riding and sweating over the giant, clunky, but remarkably functional watch. I had to start remembering the date and the day of the week. I had to stop using my preset alarms to remind me of the differences between Monday early-release days and other days for my son’s school. I had to expect to be inaccurate with my analog backup watch.
And then there was another day in September when I was out-of-town and having lunch with friends. The topic of tapioca pudding came up and none of us could recall what the origin of tapioca was. Out came the IPhone and we quickly resolved the question, fixing my partially inaccurate recollection from my Peace Corps time in Fiji that tapioca was related to dalo (taro). In fact, tapioca is from another root crop called cassava.
So these technologies may sometimes be reducing our cognitive commitments to certain information (the day and date), but they are also allowing us to reduce ambiguity in answering questions of a factual nature, and in a manner that exceeds what our natural mental capacities allow.
But what is missing for me is information convergence, where the knowledge contained in your DVR or GPS path memory is instantly accessible, exportable, importable, and available for all your needs. My car links via Bluetooth to my phone, but has separate voice memory for dialing. I can download new tunes through ITunes but my car can’t automatically grab Car Talk off NPR through the satellite radio and store it for later listening. Nor can I export my DVR content easily to my laptop for watching while at the park.
But the right technologies are available for the next step forward. The Semantic Web provides a beginning to achieve this step by providing a standard for self-describing information. Extensible Markup Language (XML) is the basis for Semantic Web. XML is an information representation language that is similar to HTML but is not merely designed for web page representation. The problem is that a representation language is useless unless every technology agrees on how to represent different information resources. Semantic Web standards provide a meta-description for XML data that makes it possible to code information in meaningful ways, where “meaningful” is defined by the capacity to share information between systems, converting information into knowledge in some sense.
Someday soon, my Ofamind.com approximation of Vannevar Bush’s Memory Extender may be able to talk to my DVR and help me find quotes from PBS’s The War, and my GPS will help me retrace the path of the California gold rush, as exported by Wikipedia. Someday soon.
