Reply #5: Your 3 taken up in order...

[HereSince1628]

Novel combinations of information often yield interesting if not radical new insights and thereby better understanding. Mathematically speaking, the number of combinations produced in a discipline depends upon the number of things that can be considered in combination. Not surprisingly this increases as an exponential function of the number of things available to combine and the number of items in each combination. Moving approaches and information from one field to another makes more possibilities for combinations available. That's the good thing...BUT...in creating more possible combinations it also creates combinations that aren't meaningful and can be confounding because of spurious correlations or the way that they twist the logic involved in interpreting the combination.

Many tools used in data collection are (predictably) biased/limited in their sampling. Many investigators are inherently and unintentionally biased in their use and interpretation. In general, to be meaningful information must be able to be viewed in the context of prevailing knowledge/paradigms. Big shifts in thinking are rare, and are often resisted initially because they don't conform to a prevailing paradigm. Scientists are people, scientific understanding is a product of people and is loaded with all the short-comings that people engage in even when every scientist knows the ideal is to eliminate sources of those problems.

The notion of non-corporal entities isn't only an issue of methodology. It's also an issue of the currrent state of understanding, and the limiting principles of science. I'd say that historic debunkings of evidence put forward for ghosts (ectoplasm, table taps, etc,) don't do the notion of spirits much good. As you might expect conceptualizations of ghosts almost by definition defy rules of demonstrably knowable beings/things. Thus they are left out of any acceptable paradigm from which meaningful empirical explorations can be launched. That is why no researcher has yet found a 'viable method to measure' them. Being outside the empirical realm for existing practical purposes puts them outside of science. That doesn't mean that scientists are closed to the notion that things outside of current empirical understanding exist. Bacteria and Viruses are excellent examples of things that existed for eons but came into the realm of empirical investigation only very recently as principles and practices progressed.