To be appropriately related. What is said in a philosophical discussion or debate should be relevant in that it should appropriately relate to the primary topic of conversation. Certain arguments and certain beliefs are related to the topic of conversation, and are worth talking about in order to understand the topic or to know what we should believe regarding the topic. Extreme forms of irrelevance are off-topic, and saying things that are somewhat irrelevant could change the subject or be a fallacious “red herring.”