It's all about the deep questions.
Theism: Appeals to Miracles
This argument is probably the one least respected by non-theists, but it just might be the one that is most respected by the every-day religious person. I will not go through every miracle that a particular culture or religion happens to adhere to; I will only offer some reasons why general skepticism of miraculous claims is warranted. I will be brief.
I will take a pretty standard definition that miracles are violations of the laws of nature. Now, many people do not even admit that miracles are possible, and even those who do admit that they are are inclined to say that they are the least probable kind of event that could happen. Basically, miracles are, on the face of it, very improbable occurrences. Their prior probability is very low. After all, many laws of nature, like the law of gravity, are confirmed countless times every day by simple observation. Can a miracle be confirmed to such a high degree that it is more plausible that the law be violated than the miracle? Well it’s possible in principle, but it’s nearly impossible in real life. It would require an enormous amount of evidence. Basically, echoing Hume, the miracle must have so much evidence backing it that if the miracle were to be false (given the evidence), than it would be an even bigger miracle than if it were true (given the evidence). The truth of this claim is pretty self-evident. P(x given e) must be greater than P(not x given e) in order to rationally favor x over not x. In other words, the “miraculousness” (or low probability) of not x must be greater than the “miraculousness” of x in order to believe that x. Suppose that your neighbor said they saw a dinosaur in your back yard. Now at least seeing a dinosaur is physically possible, given the laws of nature. Some jurrasic park-like scenario could have happened with genetic engineering. So the prior probability that you associate with that would be better than a miraculous claim (like someone claiming they saw a dinosaur walk on water in your pool outside.) What could your neighbor possibly do to convince you of that fact? If they showed you a picture, it would be vastly more probable that they photoshopped one or got one off of google. Even if they gave you video evidence, it would be way more probable that it was edited. If your neighbor grabbed 10 of his friends and they all attested to the fact that there was a dinosaur in your backyard, you would probably think they were playing a practical joke. After all, photo editing, video editing, and lying happen all the time, while dinosaurs showing up in your backyard don’t happen all the time. What if you actually saw a dinosaur walking around with your own eyes? Although that would be much stronger evidence, it probably still wouldn’t be sufficient. Couldn’t you have been dreaming? Couldn’t you have seen some other strange animal that you could’ve mistaken for a small-ish dinosaur (like an ostrich or something)? Couldn’t someone be playing an elaborate trick on you and put a small mechanical dinosaur in your back yard? Couldn’t a group of people be wearing an elaborate dinosaur costume (like the Chinese dragon)? All of these occurrences happen much more frequently than dinosaurs randomly walking around in someone’s back yard. After all, magicians do unexplainable things all the time, but no one thinks they are actually magic. The human mind is extremely susceptible to hasty generalizations, self-deception, and even outright hallucination. Now, if the dinosaur was filmed for a long period of time and put on a respectable news source like CNN, and a panel of scientists later seriously analyzed the foot prints and genetic samples of it, then the possibility that a real dinosaur was running around in your own back yard would have to be considered. Miracles face a similar problem but even worse, seeing that their prior probability is even lower. No miracle that I have ever encountered has been able to stand up to this stringent test of evidence.
One other peculiar historical fact is relevant to the discussion here. Why were alleged miracles rampant in older, more ignorant societies? Carl Sagan puts it nicely in the following quote:
“Classical Greece was replete with stories in which the gods came down to Earth and conversed with human beings. The Middle Ages were equally rich in apparitions of saints and Virgins. Gods, saints and Virgins were all recorded repeatedly over centuries by people of the highest apparent reliability. What has happened? Where have all the Virgins gone? What has happened to the Olympian gods? Have these beings simply abandoned us in recent and more skeptical times? Or could these early reports reflect the superstition and credulity and unreliability of witnesses?”
I’ll conclude with a word about miraculous healings, which seem to be the most prevalent type of miracles at least in today’s society where miraculous claims are made much less frequently. Why have all the healings been of the type that could be explainable by naturalistic means? In other words, why doesn’t god care about amputees? If there were a case where an amputee with no arm said a prayer out loud, and then his arm instantaneously regrew in front of an audience with a tattoo saying “God saves”, that would be a very strong case for a miracle. However, these kinds of miracles never happen; they are always hopelessly ambiguous. In all actuality, however, God could pretty easily convince everyone to believe in him. All he would have to do is part a few oceans, which would be the easiest task in the world for him. So, why doesn’t he?