Could it not also have been partly due to earlier scientists underestimating the degree to which qualitative phenomena derive from quantitative phenomena? Their error, then, was in tending to assume this quality was immune to study, rather than in assuming the quality itself.
Since you can say "Why? Elan vital!" to any possible observation, it is equally good at explaining all outcomes, a disguised hypothesis of maximum entropy, etcetera.
But you say earlier 'Elan vital' was greatly weakened by a piece of evidence. In that light, it's hypothesis could be stated "the mechanisms of living processes are of a different kind than the mechanisms of non-living processes, so you will not be able to study them with chemistry". This is false, but I don't think it's entirely worthless as a hypothesis, since biochemistry is noticeably different from non-living chemistry.
I think 'elan vital' makes some sense, even in a modern light. Most of the reactions in our body would not occur without enzymes, and enzymes are a characteristic feature of life. So perhaps we can say that 'elan vital' is enzymes! There is at least one experiment I can think of that could have been interpreted to show this too: I believe it involved fermentation being carried out with yeast-water (no living yeast, but clearly having their enzymes).
I suspect a part of the appeal of this saying comes from a mental unease with conflicting evidence. It is easier to think of the absence of evidence as not evidence at all, rather than as evidence against where the evidence in favor just happens to be much stronger. Perhaps it is a specific case of a general distaste for very small distinctions, especially those close to 0?
Ad hominem argumentation is another example of evidence which is usually weak, but is still evidence.
I'm reminded of Emotivism.
"Belief in belief" sounds perfectly plausible here, where the second-level belief is different: not that believers are morally superior, or believers go to heaven, but that believers are cool.
One answer is that grant-writing is an evil deed. I don't tend to that belief, or the more plausible one that offering grants is an evil deed, but I think they're worth mentioning.
Not grant-writing per se, but grant-writing in excess of one's fair share (where "fair" is whatever you deserve - this would be a significant judgment point). The situation is complicated if everyone else is already grant inflating. It seems like a similar dilemma to that of preemptive violence: the line between self-defense and offense can be fuzzy.
Assert a confidence of (1 - 1/googolplex) and your ego far exceeds that of mental patients who think they're God.
So we are considering the possibility of brain malfunctions, and deities changing reality. Fine. But what is the use of having a strictly accurate Bayesian reasoning process when your brain is malfunctioning and/or deities are changing the parameters of reality?