A typical challenge skeptics present when confronted with claims of alleged miracles is "why won't God Heal amputees?". But, would that do the job? Consider the following thought experiment: Let's suppose that God grants the miracle and multiple individuals experience a spontaneous regrowth of amputated limbs. To make the case more extreme, imagine that Nick Vujicic is among the healed ones, recovering both his legs and arms. There are multiple eye witnesses to the miracles, everyone who got healed was recorded live by multiple cameras, we have access to the medical records of each individual, we have the testimonies from the families, we have everything. If we grant all this, would that prove that the supernatural is real? If so, why? If it doesn't, then why do websites such as why won't God Heal amputees? demand miracles that will be disregarded anyway?
Logically, if we could prove that God healed amputees then it would as a corollary prove the existence of God. (it is simply the argument that; "if X is specifically observed to do Y, then X must exist"). But in practice that has two problems:
Either, if science demonstrates God's existence, in what sense is He then "super"natural and not a part of the natural world, whose business it is for science to observe and describe?
Or, if science discovered that human amputees can heal in the same way that some other simpler creatures can, not to mention plants, what reason could there be for invoking God over some yet-to-be-discovered biological mechanism?
The site you refer to is positing the existence of the Biblical God (i.e. not just any deity) and discussing whether that makes sense. The amputee issue is just a convenient vehicle for that discussion.
The term 'supernatural' is generally used by modern skeptics in the sense: "That which cannot be explained by natural processes using the natural sciences." However, any event that can be observed systematically is ipso facto subject to the natural sciences, so the definition itself precludes the existence of miracles. It's a neat little Catch-22 argument, though people often mistake it for reductio ad absurdum.
So no: skeptics will not accept any observation as evidence of a miracle, merely because framing anything as observable evidence immediately places it in the context of the natural sciences. The natural sciences posit a world of systematic, unthinking processes; faiths posit a world of intentional actions by unseen being(s). So long as both sides remain closed-minded on the issue, these debates are little better than trench warfare.
I'm not advocating either side of this dispute, mind you — I'm philosophically agnostic — I'm simply pointing out that arguments in this topic area are largely matters of rhetoric, not reason.
As an athiest who advocates for philosophy, I would suggest there would be many rational bases for attacking your attribution of the regrowth to the supernatural which by definition places the agents outside of the known laws of the universe. The claim that gods and magical beings are real is essentially the assertion that it is possible to fit outside the patterns of observable and explanatory causality, whatever its nature. Some rely on divine revelation and others like theologians a blend it with philosophical discourse. However, the naturalized epistemology which wields an empirical edge is clearly the better method. Science (whatever it may be) is practiced in such a way that one has to jump over a clear set of skeptical philosophical objections to rule out illusion, hallucination, bias, fallacy, and deception.
Human thought functions through a defeasible thinking process would essentially proceed as such:
- Evidence of lack of explanation does not in itself constitute evidence of the supernatural. Clearly history has shown the pattern that when an unexplained phenomenon occurs, the most reliably factual method to explanation has been science.
- What is the nature of the evidence that might be considered evidence of the supernatural? Regrowing limbs in a human would truly be extraordinary, however, the claim an animal regrew a limb is not. The regrowth of animal limbs has been well documented, and this fact rules out the claim that the supernatural is the only explanation for an instance of regrowth. Using Occam's razor, it's better to presume that genetic technology is related to the event rather than a magical being.
- What does psychology say about the behavior of the claimants? To pretend that people aren't often motivated in various ways to deceive themselves and others would be a grave mistake. In fact, self-deception is often by claimed evolutionary psychologists to be wired into the brain in order to conceal the detection of deception for survival's sake. To wit from WP:
Evolutionary psychology approaches self-deception as an adaptation that can improve one's results in social exchanges.
What is the structure of the argument itself that affirms the supernatural? Does the argument observe onus probandi? Does it utilize good philosophical razors? Does it abuse forms of reasoning? Does it blur the use of the deductive, inductive, and abductive? Are counter-arguments to the denial ad hoc in nature? For instance, even your question is constructed in such a way that to make the situation tenable, you engage in a series of highly improbable claims that aren't impossible, but taken together are extraordinary.
What is the nature of the empirical evidence? Did you perceive it with your own senses? Are you currently witness it or is the thought a memory open to confabulation? Is it reliable testimony from many others who are trained in the scientific method? What do scientists of different fields believe? Have geneticists, physicists, and medical doctors conferred and agree?
All in all, if one were to presume all of your highly improbable claims as fact, there's still room to rule out supernatural explanations including experimental genetic research and extraterrestrial technology. At best, one might be able to muster some plausible god-of-the-gaps-style claims, but even plausible scientific hypotheses and theories can be brought down by additional research and experimentation. I'll end with a quotation by a master of science fiction:
“Any sufficiently advanced technology is indistinguishable from magic.” - Arthur C. Clarke.
If these sorts of questions fascinate you, I'd recommend buying and reading The Demon-Haunted World by Carl Sagan who is a master of explaining science without a hint of condescension or militancy.
TL;DR: Concluding from "if amputations are permanent then there is no Christian God" that "if amputations are not permanent then there is a Christian God" is the simple logical fallacy of the inverse. We don't need to reason about the metaphysical here — basic logic suffices.
The fallacy is to inverse the "sign" of a conditional statement: Carelessly concluding that "if A, then B" implies the inverse, namely "if not A, then not B". It doesn't.
Our everyday experience is a bit deceiving here because things correlate: They happen together, like warm weather and being in the tropics. But while there is a statistical correlation, it is certainly wrong in many cases (if I'm in the tropics it is hot, but if I'm not in the tropics it can very well be hot anyway).
In this case, the website argues (and in my opinion very convincingly) that if amputations don't heal then there cannot be a Christian God. Note that it goes without saying that the condition "amputations don't heal" implies a host of other consequences, e.g. (in order of declining sanity): no biological mechanism in higher mammals allows this, our medical technology is underwhelming, there are no advanced extraterrestrial aliens helping us, there are no compassionate sorcerers or witches with advanced magic, and so on.
We can say with confidence that the permanent nature of amputations implies the absence of all these things. This argument is logically sound.
But it should be obvious that the inverse is not: occurrence of an amputation healing would not imply helpful aliens or sorcerers. Nor does it logically imply a Christian God. (I'd opt for biology or medicine.) Even if the enumeration of possible reasons were complete we would only know that one or more of them must be true, but we wouldn't know prima facie which one.
If you want to prove to me that an omnipotent and sentient being (god) exists then you want to demonstrate omnipotence and sentience of this being to me. An isolated case of people regrowing limbs doesn't show either of these traits. If we assume that regrowing limbs is "impossible" then perhaps it is the result of omnipotence, or maybe we just didn't know the world as well as we thought we did.
Regardless, the literal interpretation of amputees being healed has nothing to do with the argument. The question "Why won't God heal amputees?" is a rebuttal to the belief of some people that god directly intervenes in their life to save or protect them. For example surviving car crashes, operations, hurricanes and other natural disasters. All of those things have uncertain and unpredictable live or die outcomes. Now consider amputees; these may be innocent god-worshipping people so there is a reason for intent to heal them, but humans regrowing limbs has never been documented so we have reason to be certain of the outcome that one does not regrow limbs. Therefore, it follows that if god supposedly saves people from natural disasters, but won't heal amputees then god does not intervene to protect or heal us and anyone who thanks god for their success is merely attributing the outcomes of random events to a deity.
Your question really doesn't make any sense.
Say there's a box and someone is claiming there's a ton of gold in it. And say my position is that there is no ton of gold in the box.
So I try to pick up the box and I succeed. I pick the box up. This proves there isn't a ton of gold in the box because I can't pick up a box that weighs a ton and a ton of gold weighs at least a ton.
My argument would be, "Why can I pick up the box?"
Now, you're coming along and saying, in effect, "But if I could pick up the box, that wouldn't prove that there is a ton of gold in it. So why am I making such a big deal about being able to pick the box up?"
Do you see why that makes no sense? I'm not the one trying to prove there is a ton of gold in the box, I'm the one trying to prove that there isn't. And once I've found such a proof, why the heck would I, or anyone else, care what might or might not prove there is a ton of gold in the box? We already know there isn't because we can pick the box up.
If it doesn't, then why do websites such as why won't God Heal amputees? exist?
Because those who claim there is a god have to explain why god has never healed an amputee. If they can't do that, it's an argument against their claim.
What would or wouldn't be the consequences of your counterfactual world were amputees regrow limbs has no relevance because we don't live in that world. But yes, you're right, in that world, that amputees regrow limbs would not be evidence of god or the supernatural.
This is because terms like "god" and "supernatural" are only used for things we know are impossible. We literally call something "god-like" when it does things we know are impossible. We call something "supernatural" when it displays abilities or properties that contradict our understanding of the laws of physics or our notion of cause and effect.
Those kinds of claims will never be provable and sane, rational people will admit that they know that they require things they know are impossible and so are themselves impossible.
I believe it was David Hume who suggested that if we witnessed a miracle we would do better to disbelieve our own senses, rather than believe that something could occur that was contrary to the laws of nature.
However, having witnessed the seemingly miraculous phenomenon of ki projection, up close and very personal during an Aikido class, I would have to say that from a philosophical view it makes more sense to rewrite what you consider the laws of nature to be, given the evidence of experience. That, after all, is what science does, once a phenomenon becomes well enough understood to be explained.
If someone just tells you that arms regrew, it would be wise to follow Hume's advice and disregard that. But if you witnessed it for yourself, in a manner that precluded conjuring tricks, then you'd have to adjust what you thought could be accommodated by the description "natural".
Supernatural simply means something unexplainable happened, that is, unexplainable by the current state of science. There are many such things, Dark Matter, Dark Energy, and what the question really asks is what level of Dark Arts is sufficient to cause a rewrite of the science books. For that one would need to see repeatable cause and effect, and have some theory as to what was going on.
Still, there would be no need to invoke God, or gods, unless they were central to the explanatory theory, and there was some evidence for their existence. If the only evidence for supernatural beings were to be the regrown arms, then we'd have a circular argument of arms because of gods and gods because of arms, and that shows nothing by way of explanation.
So on the whole, like my Aikido experience, regrown arms would be interesting but unless part of a bigger picture, not proof of anything specific.
Would watching God explode disprove the claim that God is indestructible? Would watching God sin prove God imperfect? Would watching God fail to lift a rock prove that God is not omnipotent?
But "God is defined as..." However, the same goes for explanation and nature, here: asking whether some physical event is a miracle would be like asking if some divine event was the result of the laws of physics, maybe.