Student or Learner
What "as a matter of scientific fact"? Supposed "that one way of life is better,or more moral, than another" to be A, does the author mean "how could we ever treat A as a matter of scientific fact"?
Most people imagine that science cannot pose, much less answer, questions of this
sort. How could we ever say, as a matter of scientific fact, that one way of life is better,or more moral, than another? Whose definition of “better” or “moral” would we use?
While many scientists now study the evolution of morality, as well as its underlying
neurobiology, the purpose of their research is merely to describe how human beings think and behave. No one expects science to tell us how we ought to think and behave.
Controversies about human values are controversies about which science officially has no opinion.
I think you meant to ask "What does as a matter of scientific fact mean?" Your understanding of the phrase is correct.
I am not a teacher.