Saturday, November 6, 2010

Pigliucci Crosses Disciplines

On the latest Point of Inquiry podcast, Massimo Pigliucci showed up to discuss the demarcation problem -- an issue in the philosophy of science -- but actually spent the entire time discussing aspects of the sociology and psychology of science.

Again and again he moved from the philosophy to phrases like "but that's not how scientists actually work." For example, he illustrated his argument against Popperian falsifiability by mentioning the SETI project and the Drake Equation -- these are, he said, scientific endeavors that are not falsifiable. By that he means to say that SETI, informed in part by the Drake Equation, seems prepared to continue its search for extraterrestrial life indefinitely, no matter how many weeks, months, and years pass without finding any.

The Drake Equation is an inference that's meant to give some broad boundaries to the probability of intelligent extraterrestrial life. Though its input parameters are subject to some dispute, it yields testable claims about reality with any set of parameters. When Carl Sagan walked us through it on one of the episodes of Cosmos, he arrived at the answer of ten. On this version of the equation, there are either ten or not-ten instances of intelligent alien life.

The difficulty of testing this inference -- or any other specific inference drawn, in whole or in part, from the Drake Equation -- owes to the prosaic fact that outer space is huge and human beings have only begun exploring it. Our galaxy alone is 100,000 light years in diameter and another 1,000 light years in thickness. If SETI keeps looking for alien life next month despite a November yielding no newly-discovered little green men, it is not because they have moved the philosophical goalposts, but because, as a matter of contingent sociological-historical fact, they have only the tools they have, and the tools they have are paltry when set against the scale of the search.

With or without any version of the Drake Equation, it is a muddle to use the SETI project as a stand-in for science. We wouldn't look at sad old men walking along a beach hunting for coins with metal detectors and think "science epitomized!" SETI is a more advanced, more expensive, more sophisticated, higher-stakes version of that. The search for a cure for breast cancer lies somewhere between these.

These are searches, and searching for things is only one of the practices of science. All of them are informed by scientific knowledge and aided by current technology, and each is stuck in a particular historical moment and its limitations (political, economic, psychological, technological, historical, social, and so on). The way they're carried out in day-to-day practical terms has little bearing on the philosophy of science -- little bearing, that is, on the "pure" questions with which philosophy deals -- and a philosopher of science, as Pigliucci is, should clarify this rather than muddle it.

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