Because science cannot measure/ explain subjective supernatural experiences.
Of course science can. There have been many excellent, well-conducted scientific studies that tried to find the supernatural, like ESP, and ghosts, clarivoyance, etc. Just because science hasn't found it yet doesn't mean it's beyond science, it just means that it's not there (as far as we know, but that could change).
I don't recall you responding to Hutchinson's assertion that there are other things that science cannot explain, like; justice.
Exactly what do you think can't be explained about justice by science?
How can you use science to measure abstract concepts?
I don't even know what it means to measure an abstract concept. To what purpose are we measuring abstract concepts? Perhaps what you're bringing up is merely a question of logic instead of empirical examination (logic is part of science). Given a definition of justice, we can make a rough determination, using logic, whether a certain situation is more or less just. Even if there are difficult, borderline cases, that doesn't invalidate the entire enterprise. Sam Harris makes the point that health is a similar type of concept: to determine whether something will be healthy in some particular circumstance may be difficult to determine, or beyond us currently, but that doesn't invalidate the concept of health and our approach to it.
I know you started to elaborate on how one could decide if a certain Jazz performer was a genius (I really can't remember the exact word used to describe his skills.). I would disagree with you in this respect also. To me it would be a subjective determination. It can't be determined as specifically as the natural science in which Hutchinson works.
I don't deny the existence of subjectivity. No one can ever know what my experience of the color blue is, and that seems to be beyond science. Assuming it is beyond science (even though it may not stay that way forever, but let's assuming for now), that is an area that is beyond science, but it's also beyond being an objective statement about the real world. And that's the difference with claiming that God is objectively real based on an internal, subjective experience. One doesn't need to claim that my experience of the color blue is something objectively true in the real world for me to still claim that experience as an internal, subjective experience. But you cross the line when you say your internal, subjective experience of God means that God is objectively true in the real world.
How does Occam's razor help in these matter? As a scientism advocate don't you use Occam's razor to rule out the supernatural?
See above about science studying the supernatural.
Allow me to reiterate my position on scientism. There is no other process or method used to reliably find out things about the real, objective world that science doesn't use. So, if we determine something largely on logical grounds, that may not be science strictly speaking, but it's nothing that is beyond science.
