Im stuck on these premise drills. How does the contrapositive come into play? Does anybody have solution help or tips? How does one use the contrapositive to build a premise that makes the conclusion valid?
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The contrapositive is an inference we can make from any sufficient and necessary statement, and when diagramming we should always determine the contrapositive. The missing premise drills closely mirror strengthen with sufficient premise questions. Sometimes, a set of statements won't immediately "fit together," but when you take the contrapositives, the connections become clearer.
The drills are quite challenging, and one thing I like to do is assing "things" to the Xs and Ys. That is instead of If X -> Y, we could replace X with dogs and Y with pets. That would give us If Dog -> Pet.
I would find this much easier to digest than just the pure logic.
