Stephen Jay Gould on Critical Thinking

Until the time of his passing, biologist Stephen Jay Gould stood out as one of the world's best popularizers of science, most of all for his masterful storytelling. His 1985 essay "Nasty Little Facts" is an exercise in a well-told story about a scientific discovery and the reaction to the fact. It also serves as a moral about critical thinking.

Gould begins his essay with the following apparent mystery. There was a particular kind of life that scientists believed to have developed during the Cambrian period, about 510 million years ago. But then in the mid-eighties, this particular form of life was discovered, still living, in the oceans.

Following the discovery, Gould tells in this essay that he published a scientific paper laying out why the finding seemed so controversial. Being a theory of change over time, evolutionary theory, he said, needed to demonstrate why it could not be the case that a particular species form could persist for so long. He said it needed to be demonstrated to Biblical literalists that the species did not arrive readymade.

But in this essay, Gould looks back on his own initial paper and claim as pretty lousy. The sea life finding need not be controversial at all. To accept it as such, he says, means not being attentive to how good, plain, old critical thinking works, let alone scientific thinking.

Here's why. When a form of sea life was discovered to have existed that was previously believed to have existed in the Cambrian, people had a ready means to account for the fact. Biblical literalists pointed to Genesis and said the finding was evidence that species were created in their diversity at the beginning and persist as they always have. Biologists meanwhile looked at the finding and said it was only evidence that we don't have a well-preserved fossil record of life's change over time. In other words, the trouble was in the incomplete record, not in the incorrectness of evolutionary theory.

Gould's point is that any supposed fact that could be accounted for by more than one hypothesis is not a strong fact favoring any hypothesis. It's only when there is a bundle of facts where the hypothesis, the bundle, and the hypothesis's predictive power all work together that we can say we have anything like a well-developed theory.

The so-called controversy that came about in the eighties with the finding of a new form of sea life, a controversy which Gould helped to perpetuate with his scientific paper, was really a whole lot of fuss over nothing, Gould is saying, and "Nasty Little Facts" is his way of saying "my bad."