How Arguments Go Wrong-and How Bad Arguments Can Go Right

"Formal logic helps us build and evaluate rational arguments, which helps us to test claims, explain our reasoning, and keep discussions clear. The first step in learning formal logic is learning about deductive arguments -what they are, how they are structured, and how they can go wrong. The Parts of a Deductive Argument Deductive arguments are built out of premises and conclusions. For example, here is a simple deductive argument: The first two sentences are the premises. The last sentence is the conclusion. Premises are statements that support the conclusion."

"In deductive arguments, if the premises are true and the logic is valid, then the argument is sound. If an argument is sound, the conclusion is true. How Arguments Can Go Wrong There are two broad ways deductive arguments can go wrong. 1. One or more premises are incorrect. For example: The logic in this argument is valid, but the first premise is false. 2. The logic is flawed. For example: In this argument, the premises are correct, but the logic is flawed. Arguments with flawed logic are called invalid arguments."

Deductive arguments consist of premises that support a conclusion. When premises are true and the inference is valid, the argument is sound and the conclusion must be true. Deductive arguments can fail if one or more premises are false or if the logical inference is invalid. False premises can produce true conclusions by coincidence, and invalid logic can also lead to true conclusions despite flawed inference. Both incorrect premises and flawed logic can coexist while yielding a true conclusion. Assuming a poorly supported argument implies a false conclusion is the fallacy fallacy. Evaluating premises and validity is essential.

Read at Psychology Today