Here Is A Hand - Logical Form

Logical Form

The skeptical argument takes the form of modus ponens:

• If A then B.
• A.
• Therefore B.

Moore's argument flips the modus ponens structure into a modus tollens:

• If A then B.
• Not B.
• Therefore not A.

This illustrates Fred Dretske's aphorism that "ne man's modus ponens is another man's modus tollens"