Recently, I came across an intriguing question. When the Old Testament and the New Testament contradict, which one holds more authority? If you had asked me several years ago, I would have told you the Tanak for it is the foundation.
The question is leading--it sets up a problem that may or may not exist and asks you to solve it as if it does exist. It then follows along the lines of a black and white fallacy: one book or the other must be more "authoritative" than the other. Either the New Testament is supercessionist or it is plain wrong. Those are the only answers available. Since the question is usually posed to those who have already rejected the first answer, it naturally leads to the second. The New Testament is false because it contradicts the Old.