Thursday, January 28, 2010

Tales in a subdued palette of chestnut and white

Charles Sander Peirce observed that it's a poor bet to insist that science will never be able to solve some question. Make the bet, he says, and
[t]he likelihood is that it will be solved long before you could have dreamed possible. Think of Auguste Comte who when asked to name any thing that could never be found out instanced the chemical composition of the fixed stars; and almost before his book became known to the world at large, the first steps had been taken in spectral analysis.*
Yet there are certainly some questions we won't be able to solve. The problem, of course, is identifying which facts those are.

Traces of the past have been effaced, and so there are some facts about what the past was like that are unrecoverable. In explaining underdetermination to people, I use the colour of dinosaurs as an example. It may just be that the fossil record has not preserved enough for us to figure it out.

And yet researchers claim to figure it out based on microscopic bits responsible for extruding pigment; see the NYTimes article. The Sinosauropteryx, we are told, had "had a head-to-tail feathered mohawk in a subdued palette of chestnut and white stripes."

The story goes on to indicate that other scientists challenge the result, that the data set is small, and so on. And I only ever used the example in a conditional way, to say that the relevant evidence might not exist in the fossil record. I only meant say that this kind of underdetermination will arise in historical sciences. Of course we can't know with certainty which questions will be underdeterminated in this way.

Still, I need a new example.

* I give the full citation and more commentary in an old paper.


  1. Hi P.D.

    Doesn't Tim Maudlin use the example in one of his papers of the blood type of Socrates?

    (I assume you are restricting your attention to uncontroversially 'scientific' questions, as opposed to being concerned with e.g. mind/body problem or fact/value distinction or other alleged in-principle barriers to science's scope.)


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  3. Robert: I am just looking for scientific questions, so philosophical chestnuts are off the table. But anyway, mind/body stuff is not underdetermined because there are some kinds of evidence that just won't have survived in the historical record; if it's underdetermined, it is so for different reasons.

    Socrates' blood type is underdetermined because the relevant evidence is lost to the past. But it arguably is just a point of trivia and not one of scientific interest; that is, it's just a fact about one guy rather than some general fact.

  4. What about: 'what caused the big bang?' This is an important question for cosmology and there are certainly scientifically informed speculations on the matter, but I don't think anybody believes that fact can be settled.

  5. Eric: It's not clear, given the structure of spacetime, whether it makes sense to ask for a cause of the big bang. The colour of dinosaurs and Socrates' blood type are different, because the questions are clearly meaningful and the past was one determinate way or another. Underdetermination, if it arises, only arises with respect to such questions because of the contingent limitations of what has been preserved in the historical record.

  6. Why look to the past for under-determined scientific questions when the future is so much more under-determined by present evidence than the past is?

    For example: what color will the largest land animal be (if there is one) 70 million years from now?

  7. That example sounds much like a faithfull claim about science. It's almost as if science received the prophetic task to discover the truth about nature, which, by the way, ignores our tiny atempts to understand it at all.


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