While I await a reply from George to my post just below this one, let’s review again why the following claim is a self-defeating one: “Morality is subjective.” If we assume the claim is false, then we deny that morality is subjective. If we assume the claim is true, then the claim does not oblige anyone to accept the claim, since morality would just be a matter of personal opinion. That is, since there’s no external obligation on me to accept the claim, I can go ahead and accept the negation of the claim and hold that morality is objective.
There are a number of terrible consequences to holding that morality is subjective, i.e., that it’s a matter of personal opinion. For example, the claim, “murder is wrong,” would simply be an autobiographical comment, telling us about the person who made the claim rather than carrying with it the implied obligation not to murder.
While there are a plethora of other terrible consequences to holding that morality is subjective, let’s focus in again on what I was saying in the first paragraph but from a different angle. If one’s belief is that truth is objective, that is, it is not a matter of personal opinion, such a belief does not comport with the belief that morality is subjective. We would simply need to ask whether it is true that morality is subjective. In other words, if there’s no objective obligation to base morality on truth (so that morality might be objective), what is the value of making truth judgements about morality?
Consider the following claim. We’ll call it claim #1:
"There is no objective obligation on anyone to base morality upon truth."
Now, let’s negate claim #1 and call it claim #2:
"There is an objective obligation on everyone to base morality upon truth."
Notice that both these claims concern morality. Notice also that these claims directly contradict one another. We can’t (notice, moral obligation) accept both these claims since accepting both would constitute a contradictory position. We have to (notice, moral obligation) choose one or the other. If I don’t have to choose only one, then I’m permitted to be irrational. But what happens when we choose claim #1? If there’s no objective obligation to base morality on truth as claim #1 says, and if claim #2 is false, then I can base morality on falsehood, that is, I am permitted to base it on claim #2. What you ought to notice here is that both the acceptance and rejection of claim #1 prove that claim #1 is false.
Still not convinced? Let’s look at another claim and call it claim #3: “People have an objective moral obligation to base morality on falsehood.” First of all, who would accept such an idea? Secondly, what if the claim is true? If so, then the claim requires that I reject it because it assumes to be true and because it concerns morality! But if you deny claim #3, then on what do you base your denial? Do you believe that we have an objective moral obligation to base morality on truth? If so, then you deny that morality is subjective. And if we don’t have an objective moral obligation to base morality on truth, then we are permitted to accept claim #3 (which would be absurd).
What’s going on here? The point I’m making is that rationality is not possible if truth claims don’t imply or presuppose the moral obligation to accept them, nor is rationality possible if moral claims don’t imply or presuppose truth. In the Christian worldview, truth claims do imply the moral obligation to accept them. In the Christian worldview, morality must be based on truth. Therefore, as long as atheists continue to claim that morality is subjective, not only do they have no basis for calling Christians wrong, but they have no basis for calling themselves right. What is the point of reasoning, speaking or listening if no one is morally obligated to be rational? What is the point of insisting on rationality if your insistence is based on a personal opinion that no one is morally obligated to accept?
But if atheists want to claim that morality is objective, then I’d really like to hear how they justify or account for that, given their rejection of the omniscient, immutable, omnipotent, sovereign God.