[metmom]

The observation and interpretation of the data is made by a fallible human scientist who is starting with some basic assumptions about his theory or experiment. Granted, some science is pretty reliable, like chemical reactions and physics. There can be objectivity to a great degree when measuring changes with instruments, but not all science is so hard and fast.
A naturalistic approach to science is presumed because, we are being constantly told on these threads that science deals only with the natural and not the supernatural because the supernatural is outside the realm of science so science cannot address it. That is starting with a presumption that biases your interpretation of data and perhaps your observation of it.

[spunkets]

"Granted, some science is pretty reliable, like chemical reactions and physics. "

That includes biochem and in particular, the biochemical foundation for evolution. That includes the mechanisms of Genetics.

"science deals only with the natural and not the supernatural because the supernatural is outside the realm of science"

That's right, because the supernatural is not subject to the scientific method. That's a fact, not a presumption.