Standards being requested were not based on trial law.
Correct. The
legal proscription against hearsay in court derives from a specific constitutional guarantee: that of the right to confront hostile witnesses. Hearsay disallows meaningful cross-examination. If Tom is a defendant, and only Dick testifies to what he heard Harry say he saw Tom do, Tom can confront Dick, but he can't necessarily confront Harry. Because Dick is a sworn witness in this case, we presume his testimony is truthful unless Tom can successfully impeach it. But the only claim of Dick's that Tom has to impeach is whether Dick accurately reports what Harry said. None of what proceeds in court under that circumstance could test the truthfulness of Harry's claims, or put them under oath, independent of whether Dick accurately reported them. Harry's claims may be damning to Tom, but Harry may also be lying through his teeth. Because Tom cannot compel Harry to testify under oath in this case, and cannot test Harry's claims via cross-examination, his constitutional rights at trial would be denied if Dick were allowed to present that evidence. Hence hearsay is not permitted as legal testimony.
The
critical objection to hearsay does not depend on the legal definition, and in fact addresses a substantially different concern. We are already quite familiar with the limitations of witness testimony. We have addressed many of them. These give rise to a continuum of credibility in critical analysis, in contrast to a qualitative dismissal under the law. We do not necessarily dismiss hearsay evidence categorically, but we are not compelled to consider it convincingly probative. Specifically, the known degradation of evidentiary value over time and distance factors into an evaluation of how probative any given statement is. Memories not only fade over time, they become unconsciously embellished as a natural function of the narrative nature of recollection.
Accounts also degrade over distance, by which I mean the number of times a story is passed from one person to another. Commensurately our ability to assess the validity of the story diminishes rapidly with such distance. In controversial cases, the motive arises to misrepresent the original authority. For example, there are a number of statements attributed to Wernher von Braun by a woman claiming to have been his close associate. None of these allegedly damning statements can be found in primary evidence, and the woman did not publish these attributions until after von Braud died. In almost no cases can these witnesses be sworn or otherwise made to face consequences of lying. Hence we factor that into assessing reliability.
Even the most well-intentioned restatement suffers from rewording an embellishment. The intermediary is sometimes asked questions regarding the original testimony he heard, and we see an overwhelming desire to please the asker by filling in "details" that seem innocuous enough, but which are not part of the original testimony. And even when the intermediary is scrupulously faithful to what he heard, he still interprets and rewords.
Hence hearsay evidence in history is often prudently evaluated at a far lesser level of credibility than primary testimony, just on those general principles. Some of the specific problems I mention above are simply aggravating factors to that general diminishment.
The person being convinced is the one who decides what standard of evidence is going to convince them.
This is what few conspiracy theorists understand or accept. Many of them become accustomed to the echo chambers in which their scenarios are incubated. Submission to a reasonable standard of proof comes as a shock. Specifically, submission to a candid and skeptical audience means you don't get to massage their notions of sufficiency in order to compensate for a weak case that others just rubber-stamped.
Hence in response, most conspiracy theorists find some way to argue for a lower standard of proof -- the one to which they were previously accustomed. Thence the struggle over burden of proof. But the bottom line is that if you want people to believe you, you have to conform to
their standard of proof.
That can open another metadebate on whether a person's standards are reasonable, and we've had a little bit of that already. The bottom line is still that if you want to convince someone, you have to conform to his standard of proof. If you later want to argue that he rejected your claims because his standard is inappropriate, that's your prerogative. And
that argument also is only as credible as your ability to establish it to your audience's standard of proof. It's turtles all the way down.
If someone tries to prove a point in contravention of other evidence, or in contrast to the null, and the sum total of his proof is reliance upon hearsay testimony, then it's quite reasonable to reject that as insufficiently convincing. Even when the witness is authoritative, we still want additional circumstantial proof of key points. When the witness is not authoritative, the testimony most certainly cannot carry a burden of proof.