I have long thought that most college students would benefit from a course in practical reasoning. One topic in such a course would be to define and illustrate the Reductio ad Absurdum argument. The argument starts with a proposition, and then infers an absurdity from the proposition, thereby refuting the original proposition. The review quoted below mentions such an argument that implicitly starts with the proposition that fMRI scans are reliable guides to human thought. The absurdity is that fMRI scans sometimes light up in the presence of a dead Atlantic salmon, which would seem to suggest that the salmon is thinking. The conclusion: be careful what you infer from fMRI scans.
My favorite reductio ad absurdum argument starts with the proposition that all actionable knowledge must derive from randomized double-blind clinical trials (RCTs). The argument then shows that no RCTs have been performed to show the efficacy of parachutes. The absurdity is that before anyone uses a parachute when exiting a flying airplane, he must first find an RCT to prove the efficacy of parachutes. The conclusion: when you volunteer for the first such RCT, hope that you are not assigned to the control group!
(p. A15) In 2009 a group of researchers placed a dead salmon in a functional magnetic resonance imaging (fMRI) scanner and showed the fish some photos of people in social situations. Their results, presented under the title “Neural Correlates of Interspecies Perspective Taking in the Post-Mortem Atlantic Salmon,” were surprising. The scans revealed a red spot of activity centered in the salmon’s brain.
The authors of the study weren’t trying to pull a fast one on the scientific community. Nor did they believe in zombie fish. They were showing that statistics, used incorrectly, can demonstrate almost anything. Specifically, a certain type of data analysis, often used on fMRI scans, can find signal where there should be only noise.
Russell Poldrack, a psychologist at Stanford University, mentions the stunt in “The New Mind Readers: What Neuroimaging Can and Cannot Reveal About Our Thoughts.” His book, ostensibly about fMRI and its use in studying how the brain functions (hence “functional”), serves as a lesson in how the science works—or should work. Through blunders and baloney, innovation and self-correction, the young field of cognitive neuroscience is quickly evolving.
For the full review see:
(Note: the online version of the review has the date November 27, 2018 [sic], and has the title “Bookshelf; ‘The New Mind Readers’ Review: Scanning for Thoughts.”)
The book under review is:
Poldrack, Russell. The New Mind Readers: What Neuroimaging Can and Cannot Reveal About Our Thoughts. Princeton, NJ: Princeton University Press, 2018.
The parachute reductio argument is in:
Smith, Gordon C. S., and Jill P. Pell. “Parachute Use to Prevent Death and Major Trauma Related to Gravitational Challenge: Systematic Review of Randomised Controlled Trials.” BMJ 327, no. 7429 (Dec. 18, 2003): 1459-61.