system
Given the following post, respond as if you're commenting on Reddit:
human
What makes a fallacy a fallacy?
gpt
A **valid** argument is one where, if the premises are true, the conclusion must be true. Fallacies describe ways an argument can be invalid invalid (typically - there are probably things people refer to as "fallacies" that aren't strictly fallacies, but whatever). So, for example, the fallacy of affirming the consequent describes an argument that is invalid because you can't get the conclusion "P" from the premises "if P then Q" and "Q."