Informal logic is stuck in a quagmire, and has been since Aristotle. It relies upon an aspiration to certainty, but this is unrealistic and is in fact harmful for the way we think about logic. We reject as “fallacies” various argumentative forms merely because they fail to guarantee the truth of their conclusions, even though from a Bayesian perspective they provide evidence for these conclusions. Consequently, many of these are perfectly valid argumentative forms and in some cases are unavoidable. Examples include affirming the consequent, the appeal to authority (to which ad hominem may be a perfectly good response), slippery slopes, etc. It is simply false to say that use of a fallacy will undermine the logic of one’s argument.