In Who stole the door, he talks about a trick he played on some math students. You remember the times you are stressed and have disk error better than other times, so you conclude there is a correlation. You never have allergic reactions which confirms your original belief. When I go down a hill on cross country skis, I think I will fall. Some women are doctors.
Some doctors are smart.
Therefore, some women are smart. The argument is not logically valid. The argument is logically valid. It is impossible to tell whether the argument is logically valid. There are 4 cards on a table.