You brought back flashbacks on a frustrating afternoon spent trapped with a masters student in philosophy. I was a physics grad student at the time and he was

You brought back flashbacks on a frustrating afternoon spent trapped with a masters student in philosophy. I was a physics grad student at the time and he was quite keen to share with me his brilliant advancement of quantum theory. He'd essentially stumbled upon the idea of local hidden variables. I explained to him about Bell's inequality and the experiments that followed. His eyes lit up as he condescendingly explained to me that I had committed the fallacy of argument from authority. I hadn't PROVED that his system was wrong. I had merely stated that the natural world did not agree with his system. All I had done was show that the universe disagreed with him on quantum mechanics - there was no evidence that the universe was right and he was wrong. There's no reason to assume that the universe gets all the laws of physics right. By the end of the afternoon, I'd managed to get him to firmly agree that no dog has four legs. His logic: All cats have four legs. Therefore, anything that isn't a cat doesn't have four legs. All dogs are not cats. Therefore, all dogs do not have four legs. I pointed out that it was fairly obvious that there do exist dogs with four legs and that the argument was obviously fallacious (specifically at line 2). He chided me for making an Argument from Consequences. Just because his proof that no dog has four legs forces me to abandon my belief that I've encountered dogs with four legs doesn't mean that his proof is wrong. I must simply get used to accepting that I miscounted the number of legs on every dog I've ever met, no matter how unlikely that may seem. You probably assume that this guy was trolling me. Heck, if someone told me the story, I'd assume that same as well. Unfortunately, he was deadly serious and was exuding a palpable excitement as he made increasingly brilliant and counter-intuitive discoveries during our discussion. To any philosophy students who wonder why your major has such a dismal reputation, despite having the highest GRE scores of an undergraduate major and producing some truly interesting students, the answer is Greg.