Issues in argument assessment Rational persuasiveness • Some strategies for logical assessment • Refutation by counterexample • Avoiding the ‘who is to say?’ criticism • Don’t merely label the position • Argument commentary • A complete example • Commentary on the commentary

It is plain common sense that the role of an argument is to give us reasons for accepting its conclusion as true. The aim is to give an argument that the intended audience ought to be persuaded by. But we have not quite defined what it is, exactly, for an argument to do this. You might think that we have done this with the notions of deductive and inductive soundness, but that is not quite right. The reason is that even if we have reconstructed an argument perfectly, we cannot always tell whether or not the argument is sound. And that is because a sound argument must

• Rational persuasiveness 226

• Some strategies for logical assessment 235 Arguments with conditionals or generalisations as conclusions • Supposing the conclusion false

• Refutation by counterexample 239

• Avoiding the ‘who is to say?’ criticism 241

• Don’t merely label the position 243

• Argument commentary 244

• A complete example 247

• Commentary on the commentary 253

is an inductively forceful argument with true premises. Since we do not always know which propositions are true and which false, we cannot always tell whether an argument is sound or not.