Sunday, March 20, 2011

N.R. Hanson's Theory Ladenness

I remember being really impressed by Popper's writings on falsification, but over time I think it's much more of a goal than a description of science. Feyerabend did a good job of highlighting that in practice there's no demarcation between obervation and theory, and as no theory is consistent with all the facts (in part because all the known facts are rarely true), you don't simply falsify theories and reject them. But then I read N. R. Hanson's Patterns of Discovery, written in 1958, and realized that Hanson really discovered this Feyerabend point first.

Note the picture to the right. It's a bear climbing a tree. Once you have that 'theory' in your mind, you see it instantly, but without that information you see, I dunno, some bugs climing a string or something. This is an example of observation being 'theory laden'. Observation of x is shaped by prior knowledge of x. People see different things because they focus on different aspects of what is there, which invariably is multidimensional and so ambiguous.

I find it really fun to see where a good idea comes from, and like to find the original sources. It reminded me of how I was really impressed by Tyler Cowen point that we try to fit our lives into stories, but life isn't like a story, it's more like a run-on sentence. That's a really profound point, but it seems Kurt Vonnegut made that exact same point earlier!

Hanson sounds like a really interesting guy. He played trumpet at Carnegie Hall, was a hot fighter pilot in WW2 (famously looping the Golden Gate Bridge), designed the unit's logo, was a boxer, and died at 42 in a plane crash, with ten books in progress, including a history of aerodynamic theory.


Robert Johnson said...

I'm very interested to know more about why Popper's description of the process of scientific discovery has (seemingly) fallen out of favor. As far as I can tell, Popper pretty much has it right - though Bayesian reasoning certainly adds a new dimension. Maybe you'll right a future post on the topic?

Eric Falkenstein said...

I think it's just pretty clear there aren't any experiments that cause people to abandon their beliefs...everything's just one little piece of evidence, and every theory has anomalies.