The three goals of critical argumentation are to identify, analyze, and evaluate arguments. The term “argument” is used in a special sense, referring to the giving of reasons to support or criticize a claim that is questionable, or open to doubt. To say something is a successful argument in this sense means that it gives a good reason, or several reasons, to support or criticize a claim. But why should one ever have to give a reason to support a claim? One might have to because the claim is open to doubt. This observation implies that there are always two sides to an argument, and thus that an argument takes the form of a dialogue. On the one side, the argument is put forward as a reason in support of a claim. On the other side, that claim is seen as open to doubt, and the reason for giving the reason is to remove that doubt. In other words, the offering of an argument presupposes a dialogue between two sides. The notion of an argument is best elucidated in terms of its purpose when used in a dialogue. At risk of repetition, the following general statement about arguments is worth remembering throughout chapter 1 and the rest of this book. The basic purpose of offering an argument is to give a reason (or more than one) to support a claim that is subject to doubt, and thereby remove that doubt.