Extraordinary Claims Require Extraordinary Evidence

[Angrboda]

I think the OP is correct as far as it goes with respect to research studies that touch on anything  considered paranormal that challenges the materialist paradigm. The goal posts are constantly moved on researchers in those areas.

The OP and this have a specific statistical quantization that, admittedly is still subjective, but not arbitrary.  In designing studies of a hypothesis, you want to avoid two types of result.  The first, a type I error, occurs when our threshold for judging the hypothesis true is too low and we erroneously conclude that it is true when in fact we have a false positive.  The second, type II errors, are when we reject a hypothesis as false due to a false negative result to our study.

The extraordinary evidence requirement speaks to type I errors.  In most studies, there is a chance that the hypothesis could have been validated by sheer chance alone, rather than because the hypothesis is true.  We try to minimize this chance in ordinary studies, but it's always a risk that if the significance is set too low, false positives will occur.  Thus, setting a higher standard of significance is a way to guard against false positives.  In ordinary hypotheses, the consequences of a false positive typically aren't that important as the scope of application of the results is narrow.  However, where the consequences are greater, it is only prudent to demand a higher standard as the consequences of a false positive are greater.  (It's also legitimate to demand a higher standard where the mechanism of action is either implausible or completely absent.  That applies specifically to paranormal studies.)

So no, demanding extraordinary evidence for extraordinary claims isn't fuzzy and ill-defined.  It has a perfectly sensible explanation based on the statistics of testing hypotheses.

The most current work in psi is more scrupulous than any other field and yet the critics continually demand more safeguards against bias when the results are significant.

Removing potential sources of bias is not changing the statistical significance required. The two aren't related, and the reason that more stringent studies are demanded is that all too often when controls in a psi experiment are strengthened, the effect disappears. It's called replication, and it's standard in any other field. That the results so frequently evaporate upon replication is highly suspicious.