Description: Reasoning that because authorities cannot agree precisely on an issue, no conclusions can be reached at all, and minimizing the credibility of the authorities, as a result. This is a form of black and white thinking -- either we know the exact truth, or we know nothing at all.
Authority A disagrees with authority B on issue X.
Therefore, we can say nothing meaningful about issue X.
My mom says that I should study for at least 2 hours each night, and my dad says just a half hour should be fine. Neither one of them knows what they are talking about, so I should just skip studying altogether.
Explanation: A disagreement among experts does not mean that both are wrong, the answer is a compromise, or that there is no answer to be known; it simply means that there is disagreement -- that is all we can infer.
Scientists cannot agree on the age of the universe. Some say it is 13.7 billion years old, some say it is only about 13 billion years old. That’s a difference of almost a billion years! It should be clear that because there is so much disagreement, then the 6000-year-old universe should be carefully considered, as well.
Explanation: Scientists who “disagree” with the estimated age of the universe do so primarily on slightly different interpretations of the same objectively valid dating methods. The difference is fairly minute in terms of percentage. Suggesting 6000 years is valid is one thing, but doing so based on the difference in interpretation from mainstream science is completely fallacious. The differences have no bearing on the truth claim of the argument (the actual age).
Exception: When the difference in professional disagreement is critical, it should be carefully examined. For example, if two doctors were debating on what medicine to give a patient, and both were claiming that the other medicine would kill the patient.
Logically Fallacious is one of the most comprehensive collections of logical fallacies with all original examples and easy to understand descriptions; perfect for educators, debaters, or anyone who wants to improve his or her reasoning skills.
Get the book, Logically Fallacious by Bo Bennett, PhD by selecting one of the following options:
Enroll in the Mastering Logical Fallacies Online Course. Over 10 hours of video and interactive learning. Go beyond the book!
Enroll in the Fallacy-A-Day Passive Course. Sit back and learn fallacies the easy way—in just a few minutes per day, via e-mail delivery.
Have a podcast or know someone who does? Putting on a conference? Dr. Bennett is available for interviews and public speaking events. Contact him directly here.