Consequently, if any premise in such an argument is doubtful, the argument cannot establish its conclusion.
All white horses love apples.
Flash is a white horse. So Flash loves apples. The premise about white horses is irrelevant to the conclusion about Flash in the absence of the information that Flash is one of the white horses. Similarly, that Flash is a white horse is irrelevant to the conclusion without the information that things of that kind love apples. The pattern of linkage in the Flash argument is a common one for linked arguments with two premises.