NASA vs Econosophers: Inference in Science.

"There is something there. But just because your theory is good does not mean that the entities in your theory are 'really there', whatever that might mean ..." (here)

(source, Image Credit: NASA/JPL/University of Arizona)

Miss today's #MarsAnnouncement? Here's the highlights on evidence that liquid water flows on present-day Mars: https://t.co/sFKSJo7VqD

— NASA (@NASA) September 28, 2015

So, NASA discovered water flowing in the surface of Mars. That's the "entity" they discovered (although they already suspected its presence and the interested public had guessed the mysterious announcement). It's not Evian-like water, mind you; not even pure water, but water, nonetheless; briny water, to be precise. And it, too, seems fairly scarce by Earth's standards: they are not talking about the Iguazu Falls.

With all those caveats in place, how do they know water is "really there"? Did they "see" it flowing?

No, they didn't "see" it. The NASA scientists infer the existence of flowing waters from several things: salty deposits left after the water evaporates, among them. They, in other words, observed the effects and inferred the most likely cause: what Prof. Daniel Little calls "inference to the best explanation" (here).

I'm no scientist (hell, I'm just a boorish proletarian) but -- to me -- NASA's argument seems pretty convincing: their theory is a very good one. It explains a lot of things, for one. It is plausible, from an intuitive point of view, for another.

Does it mean NASA scientists are like Moses, bringing the Law inscribed in stone to the people waiting anxiously before Mount Sinai?

Obviously, not. Perhaps something else left those deposits and appears to flow in satellite pictures of the soil. My guess is that would be very improbable, but I wouldn't bet on it being impossible.

And, it goes without saying, if it turns out NASA is mistaken, it would be hugely disappointing and embarrassing to everybody, especially those guys in the video (particularly after all the publicity NASA itself gave to the announcement).

The point is -- whatever the risks involved -- if I were forced to choose between following what serious, reputable, professional scientists do for a living, and what philosophers dabbling in science (or economists dabbling in the philosophy of science) think they should do, I'd probably follow the scientists. No offence meant, Sir Karl, Prof. Friedman.

But that's me.


UPDATE:
04-10-2015. I'm getting old and my memory is not improving at all. I forgot to add this: NASA's theory -- apart from its plausibility and ability to explain much -- has another virtue. It requires no intervention from magical, metaphysical beings or entities. No Animal Spirits, Confidence Fairies, utilities, invisible hands, or disembodied ideas which "are dangerous for good or evil".