Logic / Unit 4 Logic 145 short lesson, about 20 seconds
The Truth-Table Test for Validity
Captions available
The idea
An argument is valid when no row makes all premises true and the conclusion false. Find such a row: invalid. Exhaust the rows without one: valid — certified.
In practice
Video 011's definition, now mechanical.
Where people slip
Unlike the counterexample hunt (021), this method proves validity. Exhaustion is certification.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Something wrong in this lesson? Flag it · Sources for Logic