Teapots bust. From a story at Wired:
Twitter Nerd-Fight Reveals a Long, Bizarre Scientific Feud
The editorial in the February issue of the scientific journal Cladistics didn’t exactly drop with a bang. Cladistics has around 600 subscribers—almost half of which are libraries or other institutions—and it’s aimed at “scientists working in the research fields of evolution, systematics and integrative biology,” as the journal’s summary says. It’s a journal about building evolutionary trees of life, basically. Important, but harmless, right? … the editors of Cladistics were insisting that anyone trying to build those trees of life had to use a method called parsimony—that, in fact, anyone who didn’t use parsimony wasn’t doing real science.
Science Twitter caught fire pretty fast after that.
One approach for growing these trees is called parsimony. The basic idea is that the tree with the fewest number of evolutionary changes is the most likely to be true. It’s like Occam’s razor, if Occam had been an arborist. So, for example, if you built a tree that grouped gorillas with, like, tigers instead of humans, that would mean evolution had produced the opposable thumb twice (for gorillas over there and you and me over here). But group gorillas on a branch with humans and we share some common ancestor closer to the trunk who evolved an opposable thumb just once. Parsimony says, well, that’s your tree.
It’s not the only way, of course. Another approach, “likelihood,” is about comparing different trees and running computer models for how likely types of changes are. An offshoot of that, the Bayesian approach, actually calculates the likelihood of a given tree. …
Then the first pie landed in what science writer Matt Simon calls “biology’s hidden war.” He concludes,
Building trees to make sense of life on this planet is more important than ever. By using parsimony or likelihood or other techniques to group a species with its peers, researchers can infer things like behavior. … Darwin planted the tree over 150 years ago, and each day it thickens. Now scientists just have to figure out how to grow the thing without constantly trying to refresh its roots with the blood of patriots to its cause. More.
A good deal surely depends on how evolution actually occurs. Talk to the fossils: Let’s see what they say back.
Note: Nerdfight? We like it! 🙂
See also: Maybe biological classification is more of an art exhibition than a science pursuit?