Here’s an interview with Jared Loughner’s philosophy professor, worth a full read.
The odd thing about Loughner’s syllogisms is that they’re not far off from examples Slinker might use in class. “When you teach logic, you draw a distinction between truth and inference,” says Slinker. To illustrate that, a teacher might say, “If chickens could fly upside down, then George W. Bush would be president in 2098.” The statement isn’t true. It just serves as a premise from which to draw conclusions. The purpose, says Slinker, is “to show it’s the form of the argument rather than the content that’s the expression of validity.” But that only works when talking in the abstract. In real-world logic, premises matter. “If the premises aren’t true,” says Slinker, “all bets are off.”