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6.1.1 Modus Ponens

One of the basic rules of logic, modus ponens say that ‘if P happens, then Q must happen. P happened, so Q must happen’.

For example, if it is known that ‘If the dog begins to bark, then someone is at the door’, and it is also known that ‘the dog has begun to bark’, then modus ponens says that ‘someone must be at the door’.

Modus Ponens requires exactly two references.