Two Types of Argumentation Involving Rhetorical Questions 43 Denying the antecedent is partially similar to modus tollens, having the same second premise and conclusion. Only the first premise differs, with “If B then A” replacing the premise “If A then B.” This simple change converts the argument to a logically invalid form: if whenever B is true A is true, it does not follow that A is false simply because B is false. Although it is not valid, denying the antecedent can be an effective strategy in rebutting an argument previously made by the addressee: “the antecedent is denied in an attempt to establish that the consequent [i.e., A] is not acceptable on the grounds expressed by the conditional premise” (49). In other words, although denying the antecedent cannot deductively prove that A is false, it can succeed in shifting the burden of proof for A from the speaker to the addressee. By showing that A cannot be justified on the basis of B, the speaker challenges the addressee to put forth a different justification of A. If he cannot, the speaker argues, he should abandon A. Samson’s parents’ argument is most plausibly reconstructed as denying the antecedent: Premise 1: If there were no wives to be found among your own people, then you would be justified in going to take a Philistine woman. Premise 2: There are wives to be found among your own people. Conclusion: You should not go to take a Philistine wife. This works as a presumptive argument against Samson’s apparent belief that there is nothing wrong with marrying a Philistine woman. The speakers raise and reject a hypothetical justification for such an action, challenging Samson to come up with a different rationale. The challenge is strengthened by the deliberate selection of a patently false proposition B as the subject of the second premise. By choosing such a proposition, the speaker implicitly conveys his belief that given any hypothetical proposition B such “If B then A”, B is false (50). A similar interpretation can be given to the Philistine’s statement to David in 1 Sam 17,43, another of van Selms’ examples of a reductio ad absurdum: “Am I a dog, that you come at me with sticks?” The speaker here implicitly asserts: “If I were a dog, your behavior would be justifiable. Since that is obviously not the case (nor, I believe, is any other proposition B that you might offer in justification for your behavior), your behavior is unjustified.” Support for this method of interpretation comes from cases when the argument contains a pair of RQs, as in the response of the people of Judah (49) D.M. GODDEN – D. WALTON, “Denying the Antecedent as a Legitimate Argumentative Strategy: A Dialectical Model”, Informal Logic 24 (2004) 231. BURKE claims that speakers almost never deny the antecedent, and that arguments that appear to be of this type are really intended as deductively valid modus ponens or equivalent modus tollens arguments: M.B. BURKE, “Denying the Antecedent: A Common Fallacy”, Informal Logic 16 (1994) 23-30. For discussion and rebuttal of Burke’s view, see GODDEN – WALTON, “Denying the Antecedent”. (50) Although the speakers may well believe in addition that there is no conditional “If B then A” other than the one used in the argument, i.e., that the absence of any eligible Israelite women is the only justification for marrying a Philistine, this is not essential to the argument. As shown below, in some arguments it is clear that the speakers are willing to concede the truth of conditionals aside from those utilized in the argument.