Friday, July 04, 2008

Two Thoughts on Prominent Converts

Suppose that a founder (or other prominent adherent) of some philosophy theory X later comes to repudiate this theory. Does their conversion have epistemic significance for onlookers to the debate over X?

It's often treated as evidence against X. ("Even prominent X-theorist Jane now realizes that X is fundamentally flawed!") This may be understood against the background assumptions that people typically suffer from confirmation bias, and that motivated reasoning will be especially strong in case of a view that's become entrenched in one's sense of identity. Surely, we may think, it would take compelling reasons to overcome such strong biases and cause a prominent adherent to repudiate their theory. (Okay, that's not the only possible explanation, but it might be one of several that receives a significant credence boost, thus justifying a lower credence in X.)

On the other hand, the fact that Jane changed her mind is evidence that she is less biased and irrational than your average Joe. So maybe her views -- including her past views -- are worth taking pretty seriously. This might not lead you to think X more likely true, but you might at least look more carefully for other virtues of the theory that you'd previously overlooked. After all, if someone like Jane once believed it, it can't be completely idiotic. (Well, it could be, but we're talking about shifts in your balance of credence here.) So if you previously did think X completely idiotic, I guess it's conceivable that this might actually boost your credence in X ever so slightly!

I just found that curious. Either way, I don't expect it matters much in practice, as this kind of meta-evidence will typically be swamped by the first-order reasons for or against X.

5 comments:

  1. I've sometimes wondered whether philosophers changed their views precisely to appear "less irrational than your average Joe". You know, throw in a few changes of mind over a career to cultivate a reputation for being relentlessly rational and willing to follow arguments where they take one... =)

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  2. [sorry for the deletions, but I was having problems getting my comment formatted with the right html tags. Why was the preview option removed?]

    I've sometimes wondered whether philosophers changed their views precisely to appear "less irrational than your average Joe". You know, throw in a few changes of mind over a career to cultivate a reputation for being relentlessly rational and willing to follow arguments where they take one... =)

    On the contrary, the philosophical community, with only few exceptions, tends to look down upon those who are known for changing their views. I've heard Putnam criticized on these grounds numerous times, while I can’t recall a single instance where he was praised for this reason. Similarly, to the extent that Chomsky’s transition from the ‘rules and representations’ view to the ‘minimalist theory’ via the ‘principles and parameters’ position is considered relevant to evaluate his stature as a thinker, it is usually counted against rather than in favour.

    Concerning Richard's question, it seems to me that the extra credit one might be inclined to give some view on the grounds that it was once defended by an epistemically virtuous subject is offset by the comparable increase in the probability of the new and contradictory position that this same person now holds. Thus, both increases cancel each other out, and the only remaining difference between one view and other is that the first was abandoned in the light of the second.

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  3. It seems to me that the main motivation for treating the repudiation as evidence against theory X is slightly different: if philosopher PH opposes philosophical theory X, supporters of theory X will usually argue that this is because PH does not fully understand X. This line of argument becomes much more difficult to maintain if PH is the founder of the theory (even if you think PH's repudiation indicates a specific misunderstanding, you might feel compelled to suspect the appearence of a misunderstanding).

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  4. "the philosophical community, with only few exceptions, tends to look down upon those who are known for changing their views. I've heard Putnam criticized on these grounds numerous times, while I can’t recall a single instance where he was praised for this reason."

    I tend to agree that there should be something praiseworthy about this kind of attitude of Putnam and others. But let me try to say something on the other side.

    Philosophers are generally assessing problems that have been around for very long periods of time. That means that the majority of evidence on any topic is evidence that has been around long before the last 20 years. But that means that philosophers who change their mind quickly must be overreacting to recent arguments: they are too easily swayed by the trends and fashions of the day rather than seeing the truth of the matter.

    That's over-stated, but it might be true that thoughts along these lines do something to mitigate the admirable fair-mindedness of those who change their minds frequently.

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  5. I've long wondered this about someone who changes positions a lot like Putnam.

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