Appeal to tradition, also known as appeal to common practice or argumentum ad antiquitam is a common logical fallacy in which someone proclaims his or her accuracy by noting that "this is how it's always been done." Essentially: "This is right because we've always done it this way."

The assumption behind this argument is that whatever reason led to the old methods of thinking is still valid today. If circumstances have changed, this may be a false assumption.

Examples:

• "Our society has always ridden horses. It would be foolish to start driving cars." (rebuttal: we want to travel further and horses are no longer adequate for traveling such great distances)
• "Your invention is a bad idea because it has no historical precedent." (rebuttal: the fact that something has not been previously attempted does not guarantee it will ultimately fail)
• "These rules were written 100 years ago and we have always followed them. Therefore, there is no need to change them." (rebuttal: the society in which the rules were written have changed, and thus are no longer applicable)

The opposite is the appeal to novelty, claiming something is good because it's new.

There is a well-known story in cooking that shows the folly of appeal to tradition. In this story, there is a woman who, when cooking ham, always begins by cutting off one end of the ham and throwing it away. When this mysterious behavior is questioned by a friend or family member, she admits that she does it only because her mother did it that way. Becoming curious herself, she asks her mother why she cuts the end off the ham; she, in turn, says that it is how her mother did it. When the grandmother is questioned, she reveals that she only cut the end off the ham because it wouldn't fit in her pan otherwise. There are several variations to this story; see for example [1].

See also:

• traditionalism
• common sense
• inductive reasoning