Scientific metaphors

From the NewScientist of January 22, “Farming helps slime mould spores survive” by Bob Holmes:

Slime moulds have added another skill to their impressive resumé: they practise a primitive form of farming.

… While working with several wild strains of the social amoeba Dictyostelium discoideum, Debra Brock of Rice University in Houston, Texas, noticed that a third of the strains always packaged bacteria along with their spores in [their reproductive] capsule. This means they can “seed” a food crop when they colonise a new habitat.

… With no evidence that the amoebae weed or fertilise their crop, the interaction might be better termed husbandry rather than farming, says Jacobus Boomsma at the University of Copenhagen.

So you discover a new phenomenon, the combination of bacteria together with spores in some amoebae’s reproductive capsules: what to call it?

As so often in science, researchers look to human life for a suitable metaphor to serve as the basis for terminology. In this case, the language used treats the combination of bacteria and spores as the result of intentional action on the part of the amoebae: the amoebae “package” bacteria with the spores. And the particular kind of action in this case is framed as agriculture: the amoebae “seed” a “crop” of bacteria, thus engaging in “farming” (or “husbandry”, in Boomsma’s view).

The metaphor seems innocuous to me, though given that there is in fact no imputation of intentional action on the part of the amoebae, it strikes me as silly to dispute whether farming or husbandry is the better term for the phenomenon. The metaphor makes the phenomenon memorable — so it’s fodder for science writing — but it does no scientific work, leads to no predictions about things other than the original observations.

Metaphorical framing can be problematic, though. Some of my ethologist colleagues (unsurprisingly) object to labeling certain animal behaviors as rape and others as prostitution, for example.

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