Keller sets up this argument in the, “if you don’t buy my last argument, that’s okay because of this,” position. It is the notion that the existence of suffering is equally a problem for atheists. A C. S. Lewis favorite, he is quoted in the argument, it asserts that without God any notion of good or evil is personal and therefor can’t be used as a critique of God. The argument asserts that if you are an atheist there cannot be anything good or bad, just things you like or don’t like.
The problem with this is that it doesn’t matter. The atheist does not need to provide reasons to disbelieve in god, the theist needs to provide reasons to believe.
But besides that, another problem is that it is actually somewhat testable, and is almost certainly wrong. We can check to see if people who don’t believe in God are more prone to doing bad things than those who do. Of course, this get’s complicated in a hurry, because nobody agrees on what god says is good, what to do on the Sabbath(s), what can’t I eat etc. etc. And even supposedly the same god has changed his mind over time. Beating your children and wive(s) used to be morally obligated, owning people used to be fine, etc. etc.
But even if you ignore all that, and focus on just the things the various gods seem to agree on things don’t go the theists’ way. There are societies that had laws against stealing, killing, lying, etc. before modern gods were even thought of. The countries today with the highest number of atheists have the lowest rates of those crimes. There are even studies suggesting “moral” behavior in other social animals, such as apes.
So probably, the assertion is false, but even if it isn’t, that just is evidence there’s not absolute good, not that there is a god.
The one line refutation of this argument goes something like, “You’re saying the fact that I detect suffering proves there is a god? So there is suffering. So he’s not the nice Christian God.” See previous argument.
Personal Thoughts: This argument is very popular and comes up over and over. I have a few notions about why.
Some people seem to think that this argument uses evolution against the atheist, but this is based on a misunderstanding of evolution. These people say that it’s impossible to evolve a sense of cruelty since evolution (or natural selection) is itself cruel, so evolved creatures would be used to it. Basically that’s just not how evolution works at all, and it’s totally possible to evolve so as to be unhappy with the way evolution works, or anything else for that matter.
Some people like this argument because it sorta shifts the question from “does god exist?” to “do absolute truths exist?” Some people just feel like there should be an absolute good, and an absolute evil, and using this argument you can suggest to them that if they believe in those absolutes they have to also believe in god, preferably the arguer’s version. This is not true, though. Just as there are infinite number of supernatural possibilities as the source of this absolute good, there is also the possibility that there is no source, that it is just an intrinsic law of the universe. Belief in an absolute good is certainly not evidence of any specific god or supernatural belief.
Another reason I think this argument is popular is that theists think that atheists are under the same restrictions they are. They forget that atheists don’t actually need there to be an absolute good and evil, so they think the argument is more powerful than it is.
Also, if anyone cares for my personal opinion, I don’t think there is some sort of absolute good. I also am not a complete moral relativist. I think humans, and other social animals, have evolved behaviors that manifest as moral inclinations. Also, I think we can/could use the scientific method to devise systems of behavior (a morality) to achieve agreed upon goals as a society. We could study different populations with different behaviors and determine which presents desired results. Actually, I think we do this already informally, just slowly.