Losing Digits & Gaining Banana-stands: a response to Finkelman

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I recently discovered that Balboa Island contains not one, but two banana-stands (both claim to be the original banana-stand; I assume a source of much bickering and rivalry). This struck me as novel, I had expected one banana-stand, and found two! In his recent post, Leonard Finkelman describes how scientists working on the magnificent T. rex specimen AMNH 5027 originally reconstructed it with three fingers, but later discovered a mistake. Where they expected three fingers, they found two!

Leonard suggests that the connection between ‘novelty’ in evolutionary (and evolutionary-developmental) biology is quite close to the sense of novelty I felt at discovering Balboa Island’s embarrassment of banana-stands. That is, the hey that’s weird sense of novel is closely related to the biological notion(s) of novelty:

I think that philosophers of biology generally do have something like the weirdness attributable to T. rex arms in mind when they talk about all these various kinds of novelty.

I disagree.

I take it that Leonard’s position is as follows. In both the banana-stand and T. rex cases our expectations are foiled. That is, our epistemic states relating to the number of T. rex fingers, and the number of banana-stands on Balboa island, turn out to be false. He’s right that this is a similarity. However, I think there’s an essential difference.

In biology, a ‘novelty’ is at base some new feature which deserves explanation (as Leonard nicely summarizes, there are a wide range of accounts of novelty, I assume tailored to different explanatory projects, but hopefully you’ll allow me this gross oversimplification). Leonard cites work suggesting that T. rex finger-loss and arm-shrinkage was functional: it aided in Triceratops-tipping. If that’s right (I doubt it, but it’s a nice bit of speculation regardless), then we have explained the novelty.

Does explaining the itsy-bitsy arms dissolve the trait’s novel status? No. It being a new feature of the therapod lineage stands regardless of whether or not it has been explained. However, we might no longer find the T. rex’s fingers to be novel—to find them weird—after all, we have explained them.

Distinguish between something being novel insofar as we desire to explain it, and something being novel insofar as it is a new feature. In the former case, the novelty is dissolved once we have an explanation, in the latter case it is not. It seems to me that this latter sense of novelty is significantly closer to what biologists (and, hopefully philosophers of biology?) mean.

The explanation of novelty involves explaining the emergence of new features. Part of the conceptual trickiness here (and hence the involvement of philosophers of biology) is due to the difficulty of getting traction on ‘emergence’, ‘new’ and ‘features’. If this was only about our expectations not being met, that is, ‘novelty-as-weirdness’, then I doubt we’d need such a difficult discussion…