Assignment 39 for practical work in media lab: Validity and cogency For the Departments of Media Studies by Prof Dr Sohail Ansari
Validity, Truth, Soundness, Strength, and Cogency In this lesson we will finally get around to judging whether arguments are "good" or "bad". An argument can go wrong in two ways. Remember the two claims: the claim of inference and the factual claim . Well, to check an argument you check these two claims. Is the structure , or form of the argument such that the premises actually do support the conclusion? (In asking this question you are checking the claim of inference) And, are the premises actually true? (Obviously, the factual claim) First we'll look at the claim of inference--at the form of the argument. If it passes that test, then we'll go on to look at the truth of the premises. Deductive Arguments A deductive argument is either valid or invalid . There is no in-between, no gray area. The test for validity of a deductive argument is the following: If there is any possible way for an a...