Philosophical argumentation aims at establishing the truth of a claim. The goal of persuasion is to get the audience to believe a claim whether it is true or false. Philosophical argumentation requires that one argue in good faith; persuasion does not. This is not to say that persuasive techniques are forbidden when arguing philosophically. You can and should use persuasive techniques to make your arguments more interesting, but you should not use them as substitutes for arguments.
Arguing in good faith is not the same thing as making a good argument: a person could make a terrible argument or use false premises in good faith. This is because arguing in good or bad faith is primarily a matter of intention. That said, arguments made in bad faith will tend to be bad arguments. To use an analogy, a person can prepare a turkey in good faith with the intention of making it safe and delicious. But the turkey could turn out badly or could even give the guests food poisoning. Preparing food in bad faith, to continue the analogy, would aim at deceiving guests about what they are really eating or even aim at intentionally poisoning them. As the analogy suggests, just as you would want to avoid bad faith cooks you would want to avoid those who argue in bad faith. They will not be serving up anything you should consume.
When a person argues in good faith, they intend to argue that a claim is true by using good logic and true (or at least plausible) evidence and reasons. Arguing in good faith does not require that a person believe the claim they are arguing for, but they do need to be honest about this. A person can advance an argument they disagree with as part of a good faith discussion. For example, philosophical argumentation often includes considering objections against one’s position and these objections can (and should) be made in good faith. As another example, when a philosophy presents the views of a philosopher they disagree with, they should present the arguments in good faith.
When considering arguments against your view (be they objections you raise yourself or not), arguing in good faith means using the principle of charity. Following this principle requires interpreting claims in the best possible light and reconstructing (or constructing) arguments to make them as strong as possible. There are three reasons to follow the principle. The first is that the use of this principle is the right thing to do. The second is that doing so helps avoid committing the straw person fallacy. In this context, this a fallacy in which one presents a distorted or exaggerated version of an argument and then take criticism of that version to refute the real argument. The third is practical: criticism of the best and strongest version of an argument also addresses the lesser versions.
The principle of charity should be tempered by the principle of plausibility. If you are considering another person’s argument, then the claims must be interpreted, and the argument reconstructed in a way that matches what is known about the source and the context. For example, reconstructing an argument by Descartes and including premises from quantum physics would violate the principle of plausibility. Now, on to arguing in bad faith.
Arguing in bad faith is not the same thing as arguing badly, but it usually involves making bad arguments with dubious premises. As with good faith, bad faith is a matter of intention. When a person argues in bad faith, they intend to deceive and mislead when engaged in argument. A person can engage in bad faith arguing in many ways.
One way to argue in bad faith is to knowingly use fallacies (errors in logic) to try to get the audience to accept a claim as true (or reject one as false). To illustrate, a person arguing in bad faith might make a straw person out of their opponents view or launch an ad Hominen attack against them to “refute” them.
Another way to argue in bad faith is to knowingly use persuasive devices (rhetoric) in place of evidence and reasons to get the audience to believe a claim. As noted above, you can use persuasive devices in good faith when making an argument. For example, a person skilled at both argumentation and comedy might make a hilarious but still good argument.
A third way to argue in bad faith is to use lies as premises or the conclusion of an argument. This is different from unintentionally using claims that are not true—a person can make a false claim and not be lying, since lying is a matter not just of truth but also intention. A person can also make a true claim and still be lying; this could occur because the person incorrectly believes the claim is false and is trying to deceive the audience into accepting the claim as true.
Like sorting out when someone is lying, determining when someone is arguing in bad faith can be challenging. A person who is arguing in good faith might seem to be arguing in bad faith if they unintentionally use bad logic or make false claims. Someone who is skilled at arguing in bad faith might be utterly convincing and seem to be advancing incredible arguments. Fortunately, when assessing arguments and claims you can cut through bad faith by focusing on using the methods of logic and critical thinking to sort things out.