When can we derive an ‘ought’ from an ‘is’?
Normally we can’t - which is why we can’t logically derive morality from science - but why not?
A logically valid conclusion contains only the information present in its premises.
A normative conclusion like, ‘We ought not steal,’ contains (hidden) within it value-laden information - e.g., people have inherent value/dignity and violating that value is objectively, morally wrong.
But scientific premises do not contain value-laden information, because its modus operandi of Methodological Naturalism - the view that God or anything like God need not be considered to do science - excludes the possibility of objective moral values of any kind.
But recognizing and setting aside the assumption of Methodological Naturalism (or Atheism for short) immediately makes room for the existence of objective moral values, making it logically valid to derive an ‘ought’ (a moral obligation) from an ‘is’ (a value-laden premise).
Premise 1: “... at the beginning of creation God ‘made them male and female.’
Premise 2: ‘For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh.’ So they are no longer two, but one flesh.
Conclusion: Therefore what God has joined together, let no one separate.”
(Mark 10:6-9)








