Abstract
When someone presents an argument on a charged topic and it is (credibly) alleged that the arguer has a strong personal interest and investment in the conclusion, the allegation, directed to the reception or evaluation of the argument, typically gives rise to two seemingly conflicting reactions:I. The allegation is an unwarranted diversion (a species ofargumentum ad hominemorgenetie fallacy).The prejudices or biases of the arguer are irrelevant to thecogencyof the argument. ('Cogency’ is used broadly to refer both to correct support relations, validity, in the case of deductive arguments, and to the soundness, warrant, and relevance of the premises.) In particular, it is a distraction from the crucial judgment of whether the argument is cogent to press the question of whether the arguer truly holds his conclusion on the grounds that he offers, or whether he believes it on some illicit or suspect basis (prejudice, ideology, self-interest, wishful thinking, bias).