Many Christians have this (quite strange) argument that without God there are no objective morals.
One question I seldom see asked is: On what grounds are God's moral values objective? How do you define "objective" and why are God's commands such?
I'm assuming that many of such Christians would try to argue that they are "objective" because they are not dependent on a human mind. But then it's just a circular definition: "These morals are objective because I define them to be so." The very definition of "objective" is such that these alleged moral values are "objective" and human moral values aren't. But this doesn't really tell us anything. (Nor is it established why these "morals" would be good, even assuming that the claim that they are not dependent on human minds were true. What's the justification for them to be absolutely good?)
If the definition of "objective" is "does not depend on the situation", then the Bible itself contradicts the notion. (For example, "do not kill" applies only in certain situations, not all of them. God himself commands his people to kill. You can't argue "do not kill" to be objective if God himself demands it only in certain situations but not others. This is like the very definition of subjective.)
