Sunday, May 21, 2017

Extraordinary Claims and Extraordinary Evidence

"Extraordinary claims require extraordinary evidence" is a phrase that was popularized by Carl Sagan but has its roots from at least the 18th century Enlightenment when the miracles of Christianity were being questioned by certain intellectual thinkers of the day. The most famous Enlightenment critic of Christianity was probably David Hume who wrote an essay called Of Miracles in 1748 where he states, "Suppose, for instance, that the fact, which the testimony endeavours to establish, partakes of the extraordinary and the marvellous; in that case, the evidence, resulting from the testimony, admits of a diminution, greater or less, in proportion as the fact is more or less unusual."

At first this statement may sound reasonable. For instance, I am more likely to believe you if you tell me you had breakfast this morning than I would believe you if you told me that you levitated off the ground this morning without anything holding you up. But does the fact that I believe you if you say you did something ordinary and I don't believe you if you say you did something extraordinary support the statement that "Extraordinary claims require extraordinary evidence?" Actually, it doesn't. Although I may believe that you ate breakfast this morning, I must obtain supporting evidence if I want to actually determine whether or not that fact is true. If you have cleaned up your kitchen, such evidence may be hard to find. I might have to pump out the contents of your stomach, for instance to see what you ate and when you ate it. It is one thing to say that I believe you ate breakfast because it is an "ordinary" event, but it is quite another to actually find enough evidence to validate your claim. My point is that actual validation of any event requires sufficient evidence.

It seems to me there are two major categories of "extraordinary" claims that need to be considered. The first would be a claim that can be tested in a controlled environment, like if someone claimed to be able to predict the outcome of rolling a six sided die 90% of the time, or if someone claimed to be able to levitate at whim. Those kinds of miraculous paranormal assertions can be easily tested, and to my knowledge, have never been validated as true. But the second category of "extraordinary" claims, which would include the miracles believed by Christians to be true, are events that occured only once in the past, and can not be tested in a controlled environment. I can't imagine any amount of evidence would convince Hume that such a miracle has occurred. He states, "A miracle is a violation of the laws of nature; and as a firm and unalterable experience has established these laws, the proof against a miracle, from the very nature of the fact, is as entire as any argument from experience can possibly be imagined." For this second case, I believe that the claim that "extraordinary claims require extraordinary evidence" is really just a presumptuous statement, and that no amount of evidence would ever convince the skeptic that a past single miraculous event occurred.

Let's consider an example of a hypothetical past miraculous event. Since skeptics claim that God must not care about amputees because they know of no documented case where an amputee had her limb grow back, let's suppose there was such a case. Suppose a particular person with an amputated arm wakes up one morning and the arm has completely grown back. The person, her spouse, the doctors, and her friends all claim that the last time each of them saw her she did not have an arm and now she does. Would that eye witness testimony be enough to convince the skeptic that a miracle has taken place? I don't know if it would or would not, but I do know that such eyewitness testimony is certainly not "extraordinary evidence." It is just plain old eye-witness, first person, evidence. So either the statement that "extraordinary claims require extraordinary evidence" is false or there is no reasonable evidence, including tremendous corroborated eyewitness testimony, that would convince the skeptic a miracle has occurred. As such, the proposition that "extraordinary claims require extraordinary evidence" seems totally disingenuous when it comes to any single past miracle. It seems to be simply a well-crafted phrase that sounds scientific but is not, and which allows the skeptic to dismiss any amount of supporting evidence. After all "extraordinary" is such a vague word that it is easy to dismiss all evidence as falling short of that nebulous standard.

There are examples in the Bible of extraordinary events with amazing corroborating eyewitness testimony that were dismissed by those who already had their minds made up. John 9 tells the story of a man who was blind since birth whom Jesus gave sight. The skeptical religious leaders questioned the man and his parents to see if he was really blind since birth and if Jesus had given him sight. Although he confirmed that was the case, and his parents confirmed he was their son who was blind from birth but could now see, the leaders refused to believe the truth that was right before them.

Another example of those refusing to believe that miracles could occur despite the evidence is found in Luke 16 where Jesus tells the story of a rich man and a poor man, Lazarus, who would beg for food at the rich man's gate. Upon their death, the rich man is in torment but can see Lazarus far away in comfort. The rich man asks Abraham to please send Lazarus back to his father and brothers to warn them of the reality of the afterlife so that they will not have to be tormented. Abraham's response to the rich man is, "If they do not listen to Moses and the Prophets, they will not be convinced even if someone rises from the dead." If they don't believe the testimony they already have, then no amount of "extraordinary" evidence, even someone coming back from the dead, would change their mind.

As a scientist, I am skeptical about everything. I don't believe in fairies, unicorns, extrasensory perception, telekinesis, horoscopes, or anything like that. I don't believe in them, not because I require extraordinary evidence, but because I require just sufficient evidence. Rather than ask that some unattainable "extraordinary evidence" be presented as an excuse to dismiss any supernatural act, I instead want to carefully examine the evidence and to search for a conclusion that best explains all the evidence without, a priori, ruling out a conclusion based simply on my presuppositions. In Sir Author Conan Doyle's The Sign of Four, Sherlock Holmes provides a better rule for determining whether or not a miracle may have occurred in the past when he says, "How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?"

Although I don't believe in any of the above phenomena because of the lack of evidence, I do believe there is plenty of sufficient evidence to accept the validity of certain past miraculous events including the resurrection of Jesus from the dead. The recent movie, The Case for Christ tells the true story of Lee Stobel, an award-winning journalist and skeptic who was willing to follow any sufficient evidence to find the truth. Unlike David Hume or Carl Sagan or others who make statements requiring an unattainable level of proof, a good scientist or detective or journalist will ask for sufficient evidence that can explain all of the objective facts and be willing to follow the evidence to even an improbable conclusion. Some of the most famous scientific discoveries have been made because of that mind-set. The veracity of all truth claims can be determined with sufficient evidence, and that evidence need not be "extraordinary" even for "extraordinary claims." Instead, it needs to be the same kind of first hand eye-witness or clear forensic evidence or even circumstantial evidence that clearly dispels all other reasonable options and leads to a conclusion that best explains the known facts.


  1. You are to kind to this unscientific rule. The burden of proof is on the presenter, period. I don't care how waco your claim is, if you have ordinary evidence supporting it.

    1. Sometimes a kind response will allow actual dialogue and help others see how illogical their claim actually is. I take it as a compliment that I am kind to this unscientific rule. Thanks.

  2. Nice work Mike...It seems the scientific community at large, peers and colleagues, have little or no rebuttal to your argument against Sagan and Hume.

    Biology claims the arising of a true Von Neumann machine, the cell, without evidence.

    Brian Cox in "Universal" suggests that the entire mass/energy of the universe was contained in a point entity pre-expansion where the average distance between particles was zero. That's about 10**70 ergs (from his number for the mass and E=mc**2).

    In the former the evidence is non-existence and in the latter quite lacking.

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