Correlation and Causation
Tyler Vigen · 2015
"Two variables moving together over time is never, by itself, evidence that one causes the other — with a large enough dataset, data dredging alone will always turn up strong-looking correlations between things that have nothing to do with each other."
Bachelor's degrees awarded in psychology track almost perfectly with the number of groundskeepers in Utah, year over year. Nobody thinks psychology graduates are causing a groundskeeper boom. That's the entire lesson, made visible.
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Deductive vs Inductive Reasoning
"Deduction moves from general premises to a certain conclusion (if the premises are true, the conclusion must be true); induction moves from specific observations to a probable — never certain — general conclusion, and confusing the two (treating an inductive leap as if it had deductive certainty) is a common source of bad reasoning."