A serious error in reasoning is to accept the word of someone. We should always be suspicious no matter if they are well known or not. This in mind some are authorities are more trustworthy than others. For example in the photo above is more trustworthy because it is an advertisement for basketball shoes. Who better advertise a basketball shoe than a great basketball player? If Michael Jordan suggests a basketball shoe it would be safe to take his advice. On the other hand in the add found http://www.bambootrading.com/proddetail.asp?prod=4576 would not be as trust worthy. Given the same “authority” of basketball Micheal Jordan is not as trustworthy in this situation. Chances are Jordan is not an expert in batteries.