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Valid Inferences and Valid Arguments

I would like to distinguish between the form of a valid deduction and the validity of an argument. Formal logic deals with the forms of our inferences, and not the validity of our arguments. For example, appealing to the masses is not a valid form of argument, though it could be expressed as a valid syllogism. A valid argument must have a valid logical form; or, at least, it must be expressible in such a form. But having a valid logical form is not enough. Admittedly, I haven't thought about this distinction before, and I would not be surprised if I suddenly reversed or qualified my position. This might be better discussed by focusing on examples of logical fallacies. Example 1: Begging the Question 1) If X, then ~~X 2) X 3) ~~X This is begging the question by any account. Yet, it is a valid syllogism. Example 2: Appeal to the Masses This is also a logical fallacy, but it can be expressed as a valid syllogism: 1) If everybody knows that X, then X. 2) Everybody knows that X 3