Introduction to Cognitive Science: A Logical Illusion, part 2

Consider the following statements about a hand of cards:

If there is a Jack in the hand, then there is a King in the hand, or else if there's no Jack in the hand, then there is a King in the hand.
There is a Jack in the hand.

What follows?

Did you think that there must be a King in the hand?

Why?

Click here for the correct answer...