Appeal to authority? Ah, I think you misunderstand why that is considered an invalid form of argument. An appeal to authority occurs when one appeals to an au

Appeal to authority? Ah, I think you misunderstand why that is considered an invalid form of argument. An appeal to authority occurs when one appeals to an authority in an unrelated field in order to bolster an argument from a different field. For example, while watching football yesterday, I saw a commercial where a football player told me that CenturyLink had the fastest internet. This is an implicit appeal to authority. The player is undoubtedly an authority on how to play football, but this authority is unrelated to the question of choosing a good internet service. On the other hand, if this player were to tell me which football video games were most realistic, this would not be an invalid form of argument, since he in fact has some authority on what makes a football video game realistic (Of course, there may be higher authorities yet). In this case, William Kahan actually has authority on the proper use of floating point, as the designer of IEEE 754 and a well-known authority in numerical analysis. His credentials in programming language design, granted, are weaker, but you cannot deny that his authority does in fact extend to the object of our discussion.