Which of the following statements is not deductively valid?
A)If people watch television,then they get a headache.They watch television.
Therefore,they get a headache.
B)If a student writes an abstract for a paper,then she gets a good grade.A student's paper is abstract.Therefore,the student gets a good grade.
C)If the sky is clear,then there are no clouds.The sky is clear.Therefore,there are no clouds.
D)If a black cat crosses your path,then you will have bad luck.A black cat crosses your path.Therefore,you will have bad luck.

Question

Quizplus · Accepted Answer

Statement B is not deductively valid because it commits a logical fallacy known as affirming the consequent. The premise states that writing an abstract leads to a good grade, but the conclusion is drawn from the paper being abstract, not from the student writing an abstract. This does not logically follow the given conditional statement.

Which of the Following Statements Is Not Deductively Valid