If a tool existed to measure spiritual realization, you can bet I would be posting a lot more about theurgy. Neuroscientist James Austin, in Zen and the Brain, noted that the closest thing that had been found as of 1999 was that advanced meditators seemed to have a heightened level of tonic theta-range brainwaves during waking consciousness, but the sample sizes involved in those studies were very small and all involved practitioners of either Hindu or Buddhist meditation methods. Does this relate back to magick as well? It might, and my working hypothesis would be that it should, but without more studies of Western mystics along the same lines there's no way to know for sure. Then the next question is whether or not heightened tonic theta brainwaves relate to what we normal think of as a "realized individual."
The trouble with relying on subjective measures is that, as the early psychologists discovered, introspection is unreliable and varies too much from one individual to the other. Structuralism, one of the early schools of psychology, was based on trying to correlate various introspective accounts in order to develop some sort of model of the mind's internal structure, but it eventually fell by the wayside because there was no objective way to reconcile the various interpretations of internal experiences. This, in my opinion, is about where the occult community is now with magick. Look at the varying models proposed by different individuals, all experienced occultists, and how their accounts differ. You can approach magick using any of them and seemingly get results, but the explanations of how those results happen depend upon the model employed.
As I see it the approach I'm trying to take is more akin to that of behaviorist B.F. Skinner in the 1960's. Skinner is sometimes unfairly accused of dismissing the cognitive side of psychology as irrelevant, a characterization that actually describes his predecessor John B. Watson more accurately. Skinner in fact focused his work on behavior because at the time he was working it was all that psychology could measure objectively. He would have been blown away by modern neuroscience if he had lived long enough to see it, and would have been fascinated by tools such as the functional MRI. In recent years we have in fact built many of the instruments that Skinner would have needed to probe more deeply into the inner workings of the brain and nervous system.
Skinner is generally credited as the most significant researcher in field of operant behavioral conditioning, and it is no coincidence that I use the term "operant" to describe my vision of practical magick and its workings. It's not that I think the subjective side of magical practice is irrelevant, but rather that we still lack the tools to explore it by any means other than introspection. If and when such tools become available, you can be sure that I'll do everything I can to take advantage of them in order to develop a more complete theoretical model of magical practice.