He writes:

Mark, I would suggest that Romans 1:20 would be much more obviously read as a creationist, or someone ignorant of evolution would understand it.  It seems to me Paul is talking about animals, humans, the earth, you know, made things.  But I’m no Biblical expert.

If by “creationist” you mean that Paul believes in a Creator, then of course.  If you mean Paul has some theory of “creation science” then you are wildly anachronistic. Paul is simply saying that creation testifies to a Creator.

My reader then responds to my statement that “everybody, including you, has some sense of universally binding transcendent moral goods”:

No they don’t.  Psychopaths don’t.  Moral error theorists don’t.  Some utilitarians don’t.  That’s not a great number of people, but it does rather mean that everyone is a false claim.

What pointing to radical and remarkable exception to a law illustrates is, you know, the law.  That a psychopath is unable or unwilling (it’s not clear) to acknowledge the moral law no more disproves its existence than colorblindness or a compulsion keep one’s eyes shut disproves the existence of light.  We don’t call a psychopath “morally different”.  We call him a monster, thereby testifying to our awareness of a universally binding moral law that the monster has ignored out of blindness or wilfullness.  As to moral error theorists: typically they are full of self-contradictory bunk as anybody else who tries to selectively invoke and ignore the moral law.  And utilitarians most emphatically steal from the moral law.  Demanding “the greatest good for the greatest number of people” presupposes that you should do good for people.  In other words,it relies (selectively) on the substance of the second greatest commandment, albeit whittled down by the typical blunder caused by the sin of consequentialism.

My reader then responds to my remark about ”the need for Christ to raise the natural law by grace and reveal things typically unknowable to us (like the demand to forgive and love enemies)”

Sorry Mark, but this is just plain false.  The demand to forgive and love enemies is NOT a new concept brought about by Christ, other humans had managed to arrive at this conclusion in the far East prior to and without knowledge of Christ.  Indeed, they went a step further and applied it to animals and all living things rather than just humans.  (Jainism, founded 600BC)

Love of enemies (like the existence of the One God) is something discoverable in the moral law by human reason (on rare occasions).  Still and all, it very seldom is, which is why people like Socrates and Ahknaten and the Jains stick out, just as the Jews stuck out with their monotheism in antiquity.  So Thomas teaches that no small part of the work of grace is to help us get quickly to things we otherwise might only luckily arrive at if we happened to have a lifetime of leisure and a sufficient quantity of brains to figure out.  That said, the central point here is not really about the originality of Christ's moral teaching (most of it is not original at all except in the sense that, as the eternal God who exists from the foundation of the universe, his spirit inspired it in the human heart in the first place), nor how grace perfects nature, but rather that the precepts of the moral law, be they “love your neighbor” or even something as difficult as “love your enemies” are inexplicable as *authoritative* and *transcendent* in an atheist universe.  An atheist can say he happens to choose, for whatever idiosyncratic reason of personal taste, to love his neighbor or even his enemy (though most of my conversations with atheists have included lots of derision on “love your enemy” from them).  But at the end of the day, that’s all the atheist has: personal taste resulting entirely from the chance happenstance of genes and nurture.  Yet, as you will do below in a second, the atheist almost instantly reverts to asserting binding universal moral law the moment he forgets to pretend it doesn’t exist for the special purpose of denying the existence of You Know Who.

My reader then attempts to deny the transcendence of the moral law of justice (and therefore of You Know Who as Lawgiver) by writing:

Mark, this has been shown repeatedly in the other species, from chimps to dogs to even rats.  Are you saying God has written a moral code onto the hearts of dogs and rats?  Is it not more likely that this is a way of conduct that is beneficial to the survival of many species and so has been encoded into them?

It’s curious to me that you would assume that the good of life which God placed into all living things would somehow be different from or opposite to the still greater good of human life.  Grace perfects nature, remember?  Why would you assume that the telos of maturation and survival built into the nature of all other living things by the Creator would somehow vanish in human beings?  Humans are rational animals.  So of course they seek fullness of life as all creatures do according to their kind.  But because they are rational animals, they do it with the unique faculty of reason and this involves the exercise of a moral sense sub-rational creatures lack.  That’s why we blame and praise people and why we do not blame and praise other creatures. We do not try and judge alligators for eating people, but we do try and judge Jeffrey Dahmer.  An alligator is not sinful for eating a teenage boy.  Jeffrey Dahmer is.  And his blindness or refusal to see the moral evil of his action is not proof of the non-existence of a binding and universal moral law, but of his failure to keep that law.

My reader then demonstrates the fact that he is perfectly aware of this, even in the act of pretending he is not, by selecting this sentence for what he imagines is a clinching rebuttal: “That’s why you know that raping children, taking gays out and shooting them, and lynching black people and forcibly inseminating you is *really* wrong and not merely something you happen to not prefer.”

Seems to me that many humans do not know this.  Christians and Muslims have implemented exceedingly strong anti-gay laws including the death penalty.  Islam has a death penalty for anyone leaving.  The Old Testament has the rather extreme measure of stoning your bride to death if she’s not a virgin on your wedding night.  The lynching of black people was mainly done by Christians, by a whole town, often for the ‘crime’ of a black man talking to a white woman.  And raping children, well, you know.

“You know”... what?  That Catholic priests are bound by a universal moral law known to the whole human race that says, “Do not rape children?”  Yes, I do know.  And so do you.  That's why, the moment you forget the rubbish you were attempting to parrot about the moral law not being universal and binding on all human beings, you attempt to score a point based entirely on the fact that what abusive priests did was really evil and not merely something you subjectively happen to not prefer.  You don't suggest somebody is a hypocrite for disliking chocolate ice cream that you love.  Nobody is bound by your subjective taste for chocolate.  But we are all bound by the universal moral law against child rape.  So you can, and do, and must sit in judgment of an act of child rape and you know that I am bound to do the same.  Similarly, your ridicule of Islamic brutality and sins of Christian racists rests entirely on your knowledge that the sins of Muslims and Christians against innocents are sins against the transcendent and universally binding moral law and not mere faux pas against convention like using the wrong salad fork.

So it is no proof that the moral law does not exist to point to the fact that some pretend to deny its existence, some may be blind to it, nobody keeps it well and none of us keep it perfectly.  It’s simply a restatement of “all have sinned and fallen short of the glory of God.”  As Lewis points out, the dead giveaway is that, while we may talk a good denialist game, we seldom really deny the existence of the law by our actions. Your telling “you know” is an example of this.  The dogmatic "oughts" and "ought nots" of moralistic atheists is another.  And the universal awareness of the binding nature of that law is another.  Those who try, like you, to pretend it does not exist almost instantly give the game away by either complaining about unfairness to themselves, by blaming others (as you just did) or by explaining why their evil actions aren’t really wrong or expecting praise for their virtuous actions.  All such admissions effectively acknowledge that whatever you *say*, you recognize transcendent authoritative goods.  But the one who does that is, in the words of Richard Rorty, “still, in his heart, a theologian or a metaphysician. He believes in an order beyond time and change which both determines the point of human existence and establishes a hierarchy of responsibilities.”  I can account for why you do that.  Atheism, and especially moralistic atheism, cannot, because such atheism is, in the end, self-contradictory in its struggle to escape the obvious implication that You Know Who has written the law on the hearts of all men and women.