Claim 4 of 8 · Case 05 · Relativism
If objective moral duties are real, the best explanation is a moral source beyond human beings rather than personal taste, cultural agreement, or evolution.
One claim from the free evidence repository at apologetics.pro.
Almost everyone already stands here in practice: some things really are wrong, not merely disliked. The question is what could make that true. Each candidate below is stated in its strongest form first, then answered. This is a contested question, and even if the argument works, it points to some transcendent moral source, not automatically to the God of Christianity, and thoughtful people do argue that objective morality can stand without God. It is a strong case to weigh, not a knockdown proof.
Backed by 4 pieces of evidence
Error theory, as in J. L. Mackie
Stated fairly, the view is coherent, but it cannot support what people actually mean when they condemn cruelty. If wrong only means “I disapprove,” then two people who disagree are each just reporting feelings and neither is mistaken. That collides with the strong and common sense that some acts are wrong even for the people who approve of them.Cultural consensus, or cultural relativism, as in James Rachels
Rachels shows the view carries consequences almost no one accepts. If a culture’s code defines right and wrong, then we cannot call another society’s practice, such as slavery, wrong. Reformers who oppose their own society would be wrong by definition, and moral progress would be impossible, since progress needs a standard above the culture to measure by. We do treat the end of slavery as progress over slavery, which means we are already using a standard that culture alone cannot supply.Evolution, or evolutionary ethics, as in Ruse and Wilson
This may well explain why we have moral feelings, but explaining a feeling is not the same as showing we are obligated. David Hume pointed out that you cannot move from what is the case to what ought to be the case without slipping in an ought along the way. “We evolved to feel this way” describes us. It does not tell us we are actually bound to act that way, so evolution can account for the instinct without grounding the duty.A transcendent moral source, the moral argument, as in William Lane Craig
This holds only to the degree the first three explanations fall short, which is why the honest framing matters. It points toward a source beyond human opinion and toward Christianity’s answer, without pretending to prove the whole Christian view in a single step.