Explaining Away
Discounting
A pattern of reasoning where one cause of an effect explains that effect entirely thereby reducing (need not eliminate) the need to verify other alternative causes.
Origin
The concept emerged from Bayesian reasoning and causal network theory, with the term "explaining away effect" appearing in Bayesian epistemology by Kim and Pearl in 1983. Explaining away describes a pattern where confirming one cause of an observed event reduces the probability assigned to alternative causes—also known as discounting. The Bayesian Probabilistic Causal Network approach provides prescriptions for rational calculations: when we learn that one cause explains an effect, we rationally decrease our degree of belief in alternative causes. The effect has applications from medical diagnosis to scientific reasoning.