In the study of logic, a chain argument, also known as a hypothetical argument, is an argument based on a series of conditional ("if") premises that connect to each other like links in a chain. For example, if traffic is bad, then passengers will be late. If passengers are late, then they will miss the plane. Therefore, if traffic is bad, they will miss the plane.
In a chain argument, the premises are linked by a common clause. The consequent ("then") in one premise becomes the antecedent ("if") of the premise that follows it. In the example above, the common clause is "then they will be late" / "if they are late."
A chain argument is often used to discourage someone from taking a particular action, suggesting that the apparently innocent action will lead, through a series of steps, to disaster. The argument may be sound or unsound. A chain argument is susceptible to the slippery slope fallacy, in which too little evidence exists to support the claim that one step will necessarily lead to the following step. One humorous example of the "slippery slope" fallacy in a chain argument is the series of television ads produced by DirectTV, in which a narrator argues that having cable television will lead to having a grandson in a dog collar, waking up in a roadside ditch, or some other unlikely situation.