When I lived in Tampa after college, I had the chance to serve as a mock juror, albeit one who took what I was doing extremely seriously. Twice I was called, to collect a nice check after I was done, to serve as a pretend juror as two real life legal teams on the fast track to an actual courtroom sought to try out their arguments and what sort of arguments would be most likely to appeal to an audience. One would not think that lawyers would leave up to chance what they could prepare for, no? It was fascinating for me to look at the leading questions asked to the audience members about whether it would materially affect our beliefs about a given party if it was known that they were an illegal immigrant or not, as the lawyers were not above ad hominem reasoning by any means. My time in this friendly and enjoyable side work ended one extremely long night when I spent some six hours involved in a case involving some young people who died when the metal guard rail that should have bent and flexed and kept them in the roadway instead suffered brittle failure and poked through the car door, killing some of the passengers, and the jury pool I was in had a deadlock between those who wanted to punish the estates of the foolish young people engaged in drinking and driving and those who, like myself, saw beyond the foolishness of the drivers themselves to the material properties of the rails that were meant to protect them from the full extent of their error and folly.
Those who have any interest whatsoever in matters of law or argument are used to facing different burdens of proof in different circumstances. For example, our legal system in the United States officially operates under the principle that people are innocent until proven guilty, not because human beings are in fact innocent as a general rule but because our freedom is only secure when innocence is presumed, taken for granted, given the benefit of the doubt, and where guilt must be proven and not merely asserted. As some of us have found out in our lives much to our chagrin, it is far easier to assert guilt than it is to prove innocence. The court of public opinion is not always so kind, although there are times where if someone is successful in proving their innocence that what was once immense hostility can turn into equal anger at the side who made malicious and false accusations. This does not always happen as quickly or as often as we may like, but it still happens from time to time as an antidote to despair that we will always be seen in the worst possible light. Putting a burden of proof on a given party is a recognition of the seriousness of matters of law and reputation, and the need to have a hurdle to clear before an accusation can be allowed to stick to someone.
Even in less serious matters than law there is a burden of proof that must be answered in our debates and discourses. A great deal of disagreement in the course of debates consists in what burden of proof is necessary before someone can be said to have made their point. If we are already strongly persuaded of something, we need only to see something as possible before seeing it is as likely or even certain. Where we are strongly prejudiced against something, we may demand to be disproved beyond the shadow of a doubt, where every rational or irrational question allows us to avoid conceding the point. At other times we may have no strong prejudices for or against in a given matter, but we may differ with other people as to what sort of lines of argument are suitable and appropriate and acceptable. Some people will refuse to accept any sort of circumstantial case, while others will be quite tolerant to hearing arguments that proceed according to analogies and associations. We may demand or accept different levels of proof or different types of proof in different situations and contexts. We may demand a higher standard of proof against us than we are willing to hear against someone else. There is nothing so consistent about humanity and the way it operates, after all, as rank inconsistency.
I was reminded of this matter, which is always at least a latent concern in my mind , by a book that I recently read which sought to prove various aspects of the author’s own belief system, including such matters of icons like the Shroud of Turin. The author was not alone in this sort of claim of proof. I remember, for example, reading a book one time that sought to claim that the Peshitta, the Bible in Aramaic, went back far further than it is thought to go back, making an argument based on the fact that its origin was unknown but likely to have gone back before the fourth or fifth century where the first extant copies of the New Testament in Aramaic are known. To argue that something is possible is not to argue that it is proven. We may prove something to our own standards and be content with it, but we cannot be sure what kind of standard we are being judged at by the people around us in our speaking and writing. If they are friendly or enthusiastic about listening to us, they may not make many demands on us as far as proving our point. If they are even mildly skeptical, though, if we are sloppy and careless in our research and evidence, they will leave unconvinced, and likely even more convinced of their previous inimical opinion because we have been so unconvincing in presenting our own view. Let us therefore be extremely cautious and careful in our statements claiming we have proven something, because proving ourselves of what we already want to believe is no great accomplishment at all, and certainly not anything worth trumpeting to a candid and cynical world.
 See, for example: