Ockham’s Razor
23 June 2012 at 12:52 am Peter G. Klein 2 comments
| Peter Klein |
This looks like a mighty interesting conference:
Scientific theory choice is guided by judgments of simplicity, a bias frequently referred to as “Ockham’s Razor”. But what is simplicity and how, if at all, does it help science find the truth? Should we view simple theories as means for obtaining accurate predictions, as classical statisticians recommend? Or should we believe the theories themselves, as Bayesian methods seem to justify? The aim of this workshop is to re-examine the foundations of Ockham’s razor, with a firm focus on the connections, if any, between simplicity and truth.
The conference started yesterday; here’s a report on day 1 from Cosma Shalizi. Parsimony, for example, turns out to be more complicated than it appears; here is Shalizi on (recent University of Missouri visitor) Elliott Sober:
What he mostly addressed is when parsimony . . . ranks hypotheses in the same order as likelihood. . . . The conditions needed for parsimony and likelihood to agree are rather complicated and disjunctive, making parsimony seem like a mere short-cut or hack — if you think it should be matching likelihood. He was, however, clear in saying that he didn’t think hypotheses should always be evaluated in terms of likelihood alone. He ended by suggesting that “parsimony” or “simplicity” is probably many different things in many different areas of science (safe enough), and that when there is a legitimate preference for parsimony, it can be explained “reductively”, in terms of service to some more compelling goal than sheer simplicity.
Entry filed under: - Klein -, Conferences, Methods/Methodology/Theory of Science.
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Organizations and Markets 
1.
Rafe Champion | 26 June 2012 at 6:39 pm
There is a chapter on simplicity in Popper’s “Logic of Scientific Discovery” and it is clearly not a simple matter when you get serious about it. At various times simplicity in theories has been highly prized but in this chapter a number of technical issues are explored to demonstrate that the aim of simplicity raises more problems than it solves. Theories need to be sufficiently complex to account for the complexity of the system under investigation (bearing in mind that for analytical purposes aspects of complex systems are usually isolated for investigation) and practical and technological purposes relatively simple theories are used as instruments in the knowledge that they are false but they are adequate for the domain where they are being applied.
Not entirely on topic but a heads up on Mario Rizzo’s problems at summer camp where he was once upon a time beaten up by proto-Keynesians. http://www.coordinationproblem.org/2012/06/hello-mother-hello-father-summer-camp-2012.html?cid=6a00d83451eb0069e2017742b2bbe6970d#comment-6a00d83451eb0069e2017742b2bbe6970d
He probably didn’t notice that the young Keynesians were getting grief from the proto-rational expectations boys who were in trouble with the young heterodoxers. Nobody liked the young GET nerds and you should have seen the young monetarists going at it with the proto-Keynesians on the grass behind the toilet block.
Hopefully the young Austrians get more respect at summer camp these days given that the Austrian ideas gave a credible account of the GFC and also in view of the way that Barry Smith has demonstrated that you don’t need that weird and divisive strong apriorism to do Austrian economics.
The bottom line is that Mario should have hung out with some tough proto-Austrian jocks like the Petes, Klein and Boettke.
2.
David Gordon | 28 June 2012 at 10:11 pm
The conference isn’t necessary.