This concept is represented by a set of structural equations developed by Halpern and Pearl. Houdini observing a coin flip is used to demonstrate the impossibility of one form of this concept in Max Black’s“bilking argument.” The example of a sergeant shouting is used to demonstrate how “trumping” can lead to a“redundant” form of this concept by David Lewis, who proposed analyzing this concept in terms of (*) counterfactuals. David Hume asserted we understand this relation merely through “constant conjunction.” Aristotle’s Metaphysics proposed the formal, final, material, and efficient types (10[1])of this relation. For 10 points, Hume used striking billiard balls to analyze what relation that (10[1])can lead to an effect, not to be confused with (10[1])correlation? ■END■