Modus Tollens
See arguments.
This argument moves in reverse compared to modus ponens. If P leads to Q and Q is false, you have to reject P.
$$ P \implies Q $$$$ \lnot Q $$$$ \therefore \lnot P $$See arguments.
This argument moves in reverse compared to modus ponens. If P leads to Q and Q is false, you have to reject P.
$$ P \implies Q $$$$ \lnot Q $$$$ \therefore \lnot P $$