People have often accused the "New Atheists" of using old arguments against religion, and these people are right. Apart from Victor Stenger's hard-line, physics-based arguments, every argument the new polemicists raise against religion are hundreds, if not thousands, of years old.
The people who make these accusations seem to think the age of those arguments is some sort of flaw, but they're wrong. These arguments are old because the theists have no answer for them, now that their original answer ("Shut up or we'll kill you") is out-of-bounds.
I was reminded of one of the oldest atheistic arguments while listening to the April 24th episode of Unbelievable?. If you don't know this podcast (and radio show in the UK) I recommend it. Every Sunday, the host, Justin Brierley, leads a conversation between two people with differing perspectives on the Christian faith, normally a Christian and an atheist. Despite his self-professed Christian belief, Mr. Brierley seems to be an honest, good-hearted person who actually cares about exploring the issues. If you're interested in vigorous discussions between atheists and theists, Unbelievable? is one of the most reliable sources out there. The major complaint I have is the question mark as part of the title, which makes every sentence it's in look like a fragment.
This particular show was called "Grill a Christian". They had a self-professed Christian, David Robertson, answering questions from a string of atheists, with about ten minutes devoted to each questioner. David Robertson serves as a pastor to a church which focuses on apologetics, the theists' study of how to shore up the failings of their belief system. He had all the pat answers down, and where the Christians don't have any answers, he had the Christian sophistry, flipping around the question, demanding that the questioner provide a complete answer before he'd even start to make his own answer. When David Robertson got stuck, he made the show into "Grill an Atheist" and no one on the show, not even the atheist, thought to object. This is really dirty pool -- if he doesn't have an answer, he should just say it and move on, not try to bring others down with him. (As a side note, if you ever challenged a theist and they try to get you answer the challenge first, remind them of the playground rules -- "I asked you first!" -- and get them to answer, because you've just found a hole in their world-view).
I thought it was fairly strange that Justin let David use this particular trick because it was Justin's absolute favorite argument for his god: the argument for morality. Justin claims to believe that his god -- primarily known through the bad historical fiction called the Bible -- is somehow necessary for justifying moral action. I find this the same as claiming Santa Claus is necessary to justify moral action, but Justin seems like a good guy, so I'll believe he's sincere when he says it makes sense to him.
The trouble with Justin's moral argument is it runs aground to one of those ancient atheistic arguments that Christians can't answer now that we've made them put away the thumb-screws and the burning-stake. It's called the Euthyphro Dilemma and it is older than Justin's monotheism. Literally. When Plato wrote this down, his YHVH was still married to Astarte and subservient to the chief god El. It goes something like this:
"Are things loved by a god because those things are good, or are things good because they are loved by a god?"
This one simple question, unchanged (except for the number of gods and the term used for “good”) for 2,500 years, makes a specious mess of Justin's theistic morality. If he answers “Yes” to the first question (the first “horn” of the dilemma), he's admitting that his so-called absolute morality is actually completely subjective, with his god free to command and commit murder, rape and genocide (as his god does in the bible) and those actions would be “good” because they were Justin's god's will.
If Justin assents to the first horn of the dilemma, he completely surrenders any ability to make his own moral decisions. Petty theft, murder, rape, genocide, all are impenetrable mysteries to Justin, since he isn't omniscient. Is Bernie Madoff's theft of billions of dollars right or wrong? “I don't know,” Justin must say, “since I am not privy to my god's will. If my god commanded Madoff to steal, it is correct and the man shouldn't be imprisoned. If my god didn't command it , we can punish him.”
If Justin assents to the first horn, he makes himself into a religious sociopath. Any voice he hears in his head must be obeyed, if that voice can convince him it is the still, quiet voice of his god. Murder? Theft? Rape? Genocide? All of these are commanded in his bible, so he has a precedent for them, and if he thinks the command comes from his god, it becomes not just permissible but necessary to commit those acts and more.
Think of what Justin is assenting to with that first horn! Every time you look at his happy, smiling, friendly face, you must wonder if today is the day that some whim (either of his own brain, if I'm right, or of his god, if he's right) makes him start killing those who don't worship as he does, as his god commanded him to do in the bible.
If Justin wishes to live in a society with the rest of us he must scrutinize any message that he might receive from his god, to see if it feels right to him and keeps in him line with social mores. If his god does happen to order him to do something, it's very likely Justin will turn his god down, simply because it is inconvenient for him. By assenting to that first horn, Justin has either become a madman or placed himself above his god, judging his god's orders by his own, depraved morality.
As bad as that first horn is for us, Justin probably thinks that second horn is worse. If he admits that his god only loves things which are already good, his god becomes nothing more than a herald, someone proclaiming a pre-existent fact. His god becomes no more important to morality than opera glasses are to the opera.
Between these two horns, Justin's argument from morality is reduced to nothing, just like Dr. Manhattan in the Intrinsic Field Subtractor, pulled apart by two opposing poles.
As an American, I live in a land where religion is a business. From the Presbyterian church that literally worships in front of a golden calf, to the "mega-church" that bought a sports arena because normal churches weren't large or tacky enough, to the poorest neighborhoods where there are five store-front churches in half a block, men (almost always men) use their gods to make themselves money and make themselves important. Every person that these businessmen can dominate will give one-tenth of their income (gross, not net, please), so there is a huge monetary incentive.
These businessmen (normally called "pastors") know about the Euthyphro Dilemma, of course. While they strive to keep their flock ignorant and ready to be fleeced, they have to know just a little bit more than the common man, so that they can wow the meat in the seats with their erudition.
Those pastor-businessmen who want to keep getting that ten percent have some pat answers to trundle out when one of their minions has a bright idea along the line of Socrates'. This is just the same as William Morris having an answer to the cancer-smoking link, just the same as Toyota having excuses for their cars' uncontrolled acceleration, just the same as British Petroleum having excuses for how the Gulf of Mexico spill really isn't their fault. Their business depends on it.
This spiritual businessmen, these Christian confidence men, have a pat answer to Euthyphro's Dilemma, delivered with the unctuous certainty of one who knows he can't be wrong. The response is this:
"God's nature determines what is good and what is bad."
That argument is just as wrong as Justin's assertion of Christian morality, but at least it's more subtle.
First way it's wrong at most basic level. Look at the words. Look at "Nature." That word comes from the Latin word for "birth", and appears in words such as "native" (one who was born in a place), "nation" (those born into a land), "neo-natal" (new-born) and "pre-natal" (before birth). When the pastor-businessmen say their god has a nature, they are saying their god was born, not in the sense of coming-from-Mary's-vagina, but in the sense of created-at-some-place-in-time. Only if their god came into being at one particular instant could a "nature" be imprinted on it. Of course, this sort of argument from etymology is the weakest sort of argument there is, so it's fortunate there is so much more wrong with the argument.
If the pastor asserts his god's "nature" is the source or morals, we must ask,
"Did you god choose his nature, or was your god's nature forced upon him from the outside?"
This is just Socrates' Euthyphro Dilemma restated, and it completely encapsulates the two logical possibilities. Either the theist's god picked his own nature, or something else made the choice for it. What other option could there possibly be?
Most theists, when they hear how I've phrased the question, will deny that something could force their god to do anything, because that would mean there is something more powerful than their god, and this is repugnant to them. Theists need to worship the most powerful god in the universe, otherwise, what's the point? They need that mythical power to assert their social dominance (and get their ten percent). If you happen to believe that you're a theist, perform this thought experiment: if you were presented with incontrovertible proof that your god was not the most powerful entity in the universe, could you keep worshiping it? Could you worship a silver-metal god? A second-best deity? An also-ran? This second-rate god has loved you all your life, could you abandon it once you found something more powerful?
Of course, if the theists' god chose his own nature, it plops them right back on the first horn of the old Euthyphro dilemma. Morality is arbitrary because their god could choose to change his nature. Is their god currently forbidding gay marriage and bacon? Tomorrow your god could choose a new nature that has sodomy mandatory and pork a sacrament. Is their god male? He could choose a new nature and become female. Is their god eternal? He might choose to become temporary and cease to exist. Is your god nature's "love"? You better hope he doesn't choose to make his nature "hate" or "indifference" or "walrus."
Indeed, a bit of thought shows that, if Justin's god chooses his nature, he must make that choicecompletely at random. If Justin's god has any proclivities in his choice, those proclivities are, in fact, his god's true nature and must have been forced his god from the outside.
Really, all I'm doing here is pulling apart words, splitting up Justin's god into grammatical parts. But that's the whole point. Justin's god is nothing but grammatical parts. The deity that Justin claims to worship is just a word game that he's constructed, that generations of pastor-businessmen, that millions of theistic con-men, have constructed, to stop questions and get the ten percent from the poor people they miss-lead.