What is the difference between a valid deductive argument and a sound deductive argument? a. In a sound deductive argument, it is impossible for the premises to be true and the conclusion to be false; but this says nothing about whether those premises are true. In a valid argument, it is both sound AND all of its premises are true. b. There is no difference between them: all valid arguments are sound, and vice versa. c. In a valid deductive argument, it is impossible for the premises to be true and the conclusion to be false: but this says nothing about whether those premises are true. In a sound argument, it is both valid AND all of its premises are true. d. A valid argument is not very persuasive, while a sound argument is quite persuasive.